Evidence - The parents who made their children, when they were between the ages of 2 and 10, watch videos of Pete Sampras, had children who grew up to be much better tennis players than children of parents who did not do so.

Conclusion - The parents who wish to make their children pursue tennis should make their children, when they are between the ages of 2 and 10, watch videos of legendary tennis players.

Prethink - What could be the reason for such children to be better tennis players than others just by watching videos? Maybe they learn or adapt something from the video .

(A) Pete Sampras was one of the greatest tennis players of all times and even modern tennis greats try to emulate him by watching his videos.
The greatness of Sampras does not explain the reason why the children turn to be a better player. Emulating his game can't explain the success of it.
(B) When children, who are between 2 and 10 years of age, watch Pete Sampras play, the neurons in their brains make subconscious connections as a result of which these children are able to apply some of Pete Sampras’ playing style in their own game of tennis at a later stage in life.
Looks correct. The children inherits Sampras style in their own game.
(C) Children whose parents made them watch videos of Pete Sampras when these children were more than 10 years of age also saw a marked improvement in their children’s ability to play tennis.
The children aged above 10 are not in the context of the argument.
(D) Parents who made their children, when they were between 2 and 10 years of age, watch videos of other legendary tennis players also reported that their children developed into excellent tennis players.
Although videos other legendary tennis players too might help the children, but does not help in explaining the reasoning.
(E) Some children whose parents did not expose them to videos of any tennis players also developed into excellent tennis players later in life.
This denigrate the importance of the Sampras' video and is weakening the argument.

IMO B

Researchers have discovered that parents who made their children, when they were between the ages of 2 and 10, watch videos of Pete Sampras, the legendary tennis player, had children who grew up to be much better tennis players than children of parents who did not do so. The researchers, thus, concluded that parents who wish to make their children pursue tennis should make their children, when they are between the ages of 2 and 10, watch videos of legendary tennis players.

Which of the following most strengthens the argument?

Premise: Children that watch Pete Sampras become good tennis players.
Conclusion: Therefore, watch legendary tennis players if pursuing tennis.

(A) Pete Sampras was one of the greatest tennis players of all times and even modern tennis greats try to emulate him by watching his videos.
This is irrelevant since we are focused on a specific audience: children.

(B) When children, who are between 2 and 10 years of age, watch Pete Sampras play, the neurons in their brains make subconscious connections as a result of which these children are able to apply some of Pete Sampras’ playing style in their own game of tennis at a later stage in life.
Yes! This supports the conclusion as to why children should watch good tennis players if they wish to become good.

(C) Children whose parents made them watch videos of Pete Sampras when these children were more than 10 years of age also saw a marked improvement in their children’s ability to play tennis.
This is outside of age range of 2-10. In fact, this choice weakens the conclusion. Out.

(D) Parents who made their children, when they were between 2 and 10 years of age, watch videos of other legendary tennis players also reported that their children developed into excellent tennis players.
This subtly weakens the conclusion since the children watched other legendary tennis players not Pete Sampras

(E) Some children whose parents did not expose them to videos of any tennis players also developed into excellent tennis players later in life.
This weakens the argument that the child does not have to be between the ranges of 2-10. out.

Researchers have discovered that parents who made their children, when they were between the ages of 2 and 10, watch videos of Pete Sampras, the legendary tennis player, had children who grew up to be much better tennis players than children of parents who did not do so. The researchers, thus, concluded that parents who wish to make their children pursue tennis should make their children, when they are between the ages of 2 and 10, watch videos of legendary tennis players.

Which of the following most strengthens the argument?

Cause: watch videos of Pete Sampras between the ages of 2 and 10
Effect: better tennis players than children of parents who did not do so
Aim : Strenghten

(A) Pete Sampras was one of the greatest tennis players of all times and even modern tennis greats try to emulate him by watching his videos.
This is a fact - does not strengthen.

(B) When children, who are between 2 and 10 years of age, watch Pete Sampras play, the neurons in their brains make subconscious connections as a result of which these children are able to apply some of Pete Sampras’ playing style in their own game of tennis at a later stage in life.
Correct - Strengthens the argument.

(C) Children whose parents made them watch videos of Pete Sampras when these children were more than 10 years of age also saw a marked improvement in their children’s ability to play tennis.
Weakens

(D) Parents who made their children, when they were between 2 and 10 years of age, watch videos of other legendary tennis players also reported that their children developed into excellent tennis players.
Weakens

(E) Some children whose parents did not expose them to videos of any tennis players also developed into excellent tennis players later in life.
Weakens

B and D are contenders.

IMO, the answer is D because

the conclusion of the given argument :
....concluded that parents who wish to make their children pursue tennis should make their children, when they are between the ages of 2 and 10, watch videos of legendary tennis players.

Although the argument talked about Pete Sampras, the conclusion is - legendary tennis players, not only of Pete Sampras, which made me choose D as an option.

If not D, then B is the obvious answer.

Official Explanation

Answer: D

There is a subtle scope shift taking place in the argument. While the evidence talks about Pete Sampras, the conclusion talks about legendary tennis players in general. The assumption, then, has to be that what applies to Sampras, applies to all legendary tennis players. D states this best and should be the correct answer.

(A) The conclusion is not about Pete Sampras but about legendary tennis players in general. This option fails to bring out the connection between the two.

(B) Same as A.

(C) Same as A.

(E) If anything, this option can weaken the argument by suggesting that there is no real connection between watching Pete Sampras play and children developing into great tennis players.
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GMATNinja VeritasKarishma if you guys can provide alternate explanation by B is wrong and D is correct

Posted from my mobile device

Strengthening- We have to make conclusion strong. Conclusion- For being better tennis player, children must watch videos of legendary tennis players, between 2 to 10 age.

(A) Pete Sampras was one of the greatest tennis players of all times and even modern tennis greats try to emulate him by watching his videos. -> Incorrect. Conclusion is about children.

(B) When children, who are between 2 and 10 years of age, watch Pete Sampras play, the neurons in their brains make subconscious connections as a result of which these children are able to apply some of Pete Sampras’ playing style in their own game of tennis at a later stage in life. -> subconscious mind is correct, but "Pete Sampras’ playing style" is not we are talking in conclusion.

(C) Children whose parents made them watch videos of Pete Sampras when these children were more than 10 years of age also saw a marked improvement in their children’s ability to play tennis. -> It is weakening the conclusion.

(D) Parents who made their children, when they were between 2 and 10 years of age, watch videos of other legendary tennis players also reported that their children developed into excellent tennis players. ->It is better than B. Correct.

(E) Some children whose parents did not expose them to videos of any tennis players also developed into excellent tennis players later in life. -> Weakening.

So, I think D.

Research shows that when kids watched videos of Pete Sampras, they became much better tennis players than children of parents who did not do so.

Conclusion: To make children great at tennis, show them videos of legendary tennis players.

We need to strengthen the conclusion that showing videos of legendary tennis players will make kids great at tennis. The research only supports seeing Pete Sampras' matches.

Option (D) tells us that watching matches of other legendary tennis players is also beneficial. This strengthens the conclusion that watching matches of legendary tennis players will make kids good at tennis.

(B) When children, who are between 2 and 10 years of age, watch Pete Sampras play, the neurons in their brains make subconscious connections as a result of which these children are able to apply some of Pete Sampras’ playing style in their own game of tennis at a later stage in life.

Option (B) tells us why children who watch matches of Pete Sampras are able to do better. But that does not mean that the same thing will happen when kids watch matches of other legendary players too.
Then does this help our conclusion that to make children great at tennis, show them videos of legendary tennis players? No. It just explains why researchers observe that kids who watch Pete Sampras' matches do well in tennis. Does the same thing happen with other legendary players too? We are not given.

Answer (D)
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Parents made kids (2 to 10 yrs) watch PS (legend) ==> Kids turned out to be better players (than the kids whose parents did not make them watch PS)

© Parents wish their kids pursue tennis ==> make the kids watch videos of (perhaps most) legend tennis players.

Which of the following most strengthens the argument?

(A) So what? Yeah we get it PS was a legend but what about watching videos of tennis players except PS?
(B) Again PS was a great player and watching his game would make your kid a master(probably) with all these things happening to him when he watches the his games, but what about other players?
(C) Says, watching PS games to get better is not restricted to age but again the same problem as before.
(E) If E is true, Well then there is no point in watching PS videos or any other legend tennis player's videos.
D is correct. I hope somebody finds this useful.
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