Parents who wish to provide a strong foundation for the musical ability of their children should provide them with a good musical education. Since formal instruction is often a part a good musical education, parents who wish to provide this strong foundation need to ensure that their children receive formal instruction.
The passage states two opinions, one about what parents "should" do and one about what parents "need" to do.
At the same time, only the second opinion is a conclusion for which support is provided in the passage. So, this question will likely focus on that conclusion since a flaw in an argument is generally a flaw in how a conclusion is supported.
So, the conclusion we're concerned with is the following:
parents who wish to provide this strong foundation need to ensure that their children receive formal instruction.
The support for the conclusion is the following:
formal instruction is often a part a good musical education
An issue with the reasoning of the argument that we may pick up on is that the support for the conclusion is that formal instruction is "often" part of a good musical education whereas the conclusion is that parents who wish to provide a strong foundation for musical ability "need" to ensure that their children receive formal instruction.
The reason that's an issue is that, if formal instruction is not always but only often part of a good musical education, then maybe it is not needed.
After all, if formal instruction is not always part of a good musical education, then apparently, one can have a good musical education without formal instruction.
The reasoning is most vulnerable to criticism on the grounds that it fails to consider that
This is a Logical Flaw question, and the correct answer will mention something such that the argument's failure to consider it constitutes a flaw in the argument.
One way to evaluate whether failure to consider something constitutes a flaw in an argument is to determine whether what's not considered is a weakener. If what's not considered weakens the argument, then failing to consider it is a flaw in the argument.
Thus, the correct answer to this question will be basically a weakener. In other words, if the correct answer is true, the argument doesn't work.
(A) parents might not be the only source of a child’s musical education
Regardless of whether parents are always the only source of a child's musical education, it could still be the case that, if parents do "wish to provide" a strong musical foundation, they need to ensure that their children receive formal instruction.
After all, if parents are the ones providing the foundation, then they are the ones who must ensure that everything needed for the foundation is provided, including, if necessary, formal instruction.
Eliminate.
(B) some children might not be interested in receiving a strong foundation for their musical ability
Notice that the argument is not about whether anyone is interested in receiving a strong foundation for musical ability.
Rather, it's about what parents must do if they wish to provide a strong foundation for musical ability.
If a child is not interested in receiving such a foundation, then the parents don't need to do anything.
At the same time, if parents do decide to provide such a strong foundation, then given what the argument says, it appears that they need to ensure that their children receive formal instruction.
So, the argument works even if this choice is true.
Eliminate.
(C) there are many examples of people with formal instruction whose musical ability is poor
The fact that something is not sufficient for achieving something does not mean that it's not necessary.
So, even if there are examples of people with formal instruction whose musical ability is poor, meaning that formal instruction is not sufficient for strong musical ability, it could still be the case that formal instruction is necessary for developing a strong musical foundation.
Thus, the argument works fine even if there are many examples of people with formal instruction whose musical ability is poor.
Eliminate.
(D) formal instruction might not always be a part of a good musical education
This choice is interesting.
After all, as we saw in our above analysis of the argument, the argument supports a conclusion about what parents "need" to do with a fact about what is "often" true, which is that "formal instruction is often a part a good musical education."
So, the issue with the argument is that supporting the conclusion with the fact that formal instruction is "often" part of a good musical education isn't quite logical. After all, something that is "often" part of a good musical education may not be needed for providing a strong foundation. After all, apparently, a good musical education is possible without formal instruction, if formal instruction is "often," but not "always," part of a good musical education.
So, we see that the issue with the argument is that it jumps from support that formal instruction is "often" part of a good musical education to the conclusion that it's needed without considering that it may not be needed because it's not "always" part of a good musical education.
Thus, we can say that the argument is flawed because it fails to consider that formal instruction may not always be part of a good musical education.
(Note: Some users have mentioned that, in saying that formal instruction is "often" part of a good musical education, the argument has already implied what this choice says, and that's true. At the same time in jumping from that evidence to the conclusion, the argument fails to consider what it has already implied. So, this choice still presents what the argument has failed to consider.)
Keep.
(E) some children might become good musicians even if they have not had good musical educations
Notice that the argument is about what parents must do if they wish to "provide a strong foundation."
The argument is not about what's necessary in general for becoming "good musicians."
Even if it's possible for children to "become a good musicians" without formal instruction, it still could be the case that, for parents to
"provide a strong foundation," they need to ensure that their children receive formal instruction.
So, the argument works fine even if this choice is true.
Eliminate.
Correct answer: D