Explorers of the Northern regions in the early 1700s observed the nati

ARGUMENT
[prem] horses were introduced in the 1500s;
[prem] explorer observed natives with mandolin of horse-hair in the 1700s;
[con] natives developed mandolin between 1500-1700s;
[asum] mandolin's were first developed using HORSE-HAIR, rather than something else.

ASSUMPTION
(A) irev;
(B) irev;
(C) irev;
(E) irev;

Ans (D) if the mandolin was first developed without horse-hair then the conclusion would fall.

Explorers of the Northern regions in the early 1700s observed the natives playing an instrument similar to the mandolin. The instrument was strung with horse hair. Horses were not introduced into the New World until the 1500s. Thus, we can conclude that natives developed the instrument sometime between the introduction of horses to the New World and the time of the explorers in the early 1700s.

in 1700s explorers observed natives play instruments that the string was made with horsehair.
horses were introduced in 1500s.
the author conclude that native developed the instrument between 1500s and 1700s.

but what if the instrument were not made with horsehair since the beginning but made with something else;
the instrument can be developed before and change to horsehair when horsehair were introduced.
Therefore, C; the author must have assumed that the horsehair were used since the earliest development of the instrument.
C

we can conclude that natives developed the instrument sometime between the introduction of horses to the New World .....to support this conclusion....the instrument must be first developed using horse hair not with any other material....
(D) Since it was first developed, the instrument was made with horse hair..... supports the reasoning...

OA:D

Ans: D

conclusion: natives developed the instrument sometime between the introduction of horses to the New World and the time of the explorers in the early 1700s

D)Since it was first developed, the instrument was made with horse hair.

they could used something else to make the instrument. So , author must assumed that when it was first developed, they used horse hair.

D is the answer.

Premise: Explorers of the Northern regions in the early 1700s observed the natives playing an instrument similar to the mandolin. The instrument was strung with horse hair. Horses were not introduced into the New World until the 1500s.
Conclusion: Thus, we can conclude that natives developed the instrument sometime between the introduction of horses to the New World and the time of the explorers in the early 1700s.

The author is concluding that the instrument was developed by the natives sometime between the introduction of horses to the New World and the tie of the explorers in the early 1700s. This conclusion is based on the premise that horses were not introduced into the New World until the 1500s, hence the instrument ought to be invented after the introduction of horses. What can flaw this argument is that the natives developed the instrument earlier on than the period suggested by the authors conclusion, except that instead of using horse hairs, the natives used a different material as strings for the instrument. So, for the argument to hold water, then it has to be assumed that only horse hairs were used as strings for the instrument since its invention.

This is exactly what option D states, hence the answer has to be D in my view.

(A) Natives used the mandolin-like instrument in all their religious events. Irrelevant.

(B) Using horse hair in the mandolin-like instrument was one of the natives’ earliest uses of horse hair. This doesn't save the argument from a potential flaw whereby the instrument was developed earlier before horses were introduced using a different material as string prior to time that the explorers visited the region. Hence B is not the necessary assumption on which the argument relies.

(C) This instrument was used by natives throughout North America. Irrelevant.

(D) Since it was first developed, the instrument was made with horse hair. Correct.

(E) Explorers in the 1700s were the first to document natives’ use of horse hair. Irrelevant.

Official Explanation

Natives could have initially developed their mandolin-like instrument with strings made from something other than horse hair, perhaps tree bark. In order for the conclusion in the argument to be valid, we must assume that the instrument was first developed with horse hair. Selection (D) is the assumption upon which the conclusion is based.