A scholar discovered an unlabeled nineteenth-century

I got to B, because the author gives 2 possible explanations why W's poem were found:
1. private souvenir of the voice of the famous poet
2. actors recorded poems that were familiar to public.
the conclusion then states that it is likely to be W's voice. It might be the case that W's poems were not familiar to public. Thus, second explanation is not valid.

B exactly states the above said:
phenomenon - 2 sub types.
one eliminated because of the inference from the conclusion/premises.

this is the first time when I see such type of question.

General Description: This question asks you to find the description of the method by which the argument proceeds.

A. Incorrect. The argument does offer several pieces of evidence, but they do not point to the conclusion independently of one another. That is, taking any one of the argument's pieces of evidence alone does not support the conclusion; it is only together that the evidence supports the conclusion.

B. Correct. The "phenomenon" is the nineteenth century practice of recording poetry for noncommercial purposes. The "two subtypes" are

(i) "[those made as] rare private souvenirs of the voices of famous poets"
(ii) "[those made] as publicity stunts, in which actors recorded poems that were familiar to the public."

In the "particular case" of the recording in question, the argument eliminates the second subtype by pointing out that the poem on that recording "was never even published," that is, is not a poem that would likely have been familiar to the public. Since this response most completely and accurately describes the method of the argument in the passage, it is the best answer.

C. Incorrect. There are several statements in the passage that could be construed as "general principle," but the argument does not attempt to demonstrate that any of them is violated in the particular case in question

D. Incorrect. There are "two apparently mutually exclusive alternatives" presented- namely, that a certain recording of poetry made in the nineteenth century was made either as a souvenir of the voice of a famous poet, or else as a publicity stunt in which an actor recorded a well-known poem. But the argument does not attempt to show that these two alternatives are compatible with one another.

E. Incorrect. The argument can be construed as "explaining the historical context of an incident," though it may be debatable whether a recording counts as an "incident." But even if it does, this response is incorrect, because the argument does not attempt to demonstrate that two scenarios are equally likely. Can the contrary, the argument purports to show that one scenario is more likely than the other.

Difficulty Level: Difficult

Tips and Pitfalls: In answering questions about an argument's method, be careful to compare completely the methods of support described in the responses to the argument in the passage: If a response's method does not correspond exactly to that used in the argument, that response is not the best answer.

(B) distinguishing a phenomenon into two subtypes and then for a particular case eliminating one of those subtypes.

B perfectly explains the passage. Right answer

A scholar discovered an unlabeled nineteenth-century recording of someone reciting a poem written by Walt Whitman. During the nineteenth century,recordings of poetry were not made for wide commercial sale. Rather, they were made either as rare private souvenirs of the voices of famous poets or as publicity stunts in which actors recorded poems that were familiar to the
public. Since the Whitman poem in the recording was never even published, it is likely that the voice in the recording is actually Whitman???s.

The argument proceeds by???
(A) offering several pieces of evidence, each of which independently points to the same conclusion.
(B) distinguishing a phenomenon into two subtypes and then for a particular case eliminating one of those subtypes.
(C) offering a general principle and then demonstrating that the general principle is violated in this particular case.
(D) showing that two apparently mutually exclusive alternatives are actually compatible with each other.
(E) explaining the historical context of an incident in order to demonstrate that each of the two possible scenarios involving the incident is as likely as the other.

the answer must be C right sir?

The correct answer is B, not C. You can check the OA under the spoiler in the original post.

How do we eliminated option C? (C) offering a general principle and then demonstrating that the general principle is violated in this particular case.

For violating the principle the language needs attention to be paid. If it had been violation then both reasons for which the recordings were made must be violated. If scholar choses one reason then it is not a violation of other - it's elimination.

A scholar discovered an unlabeled nineteenth-century recording of someone reciting a poem written by Walt Whitman. During the nineteenth century,recordings of poetry were not made for wide commercial sale. Rather, they were made either as rare private souvenirs of the voices of famous poets or as publicity stunts in which actors recorded poems that were familiar to the public. Since the Whitman poem in the recording was never even published, it is likely that the voice in the recording is actually Whitman’s.

The argument proceeds by…
(A) offering several pieces of evidence, each of which independently points to the same conclusion.
(B) distinguishing a phenomenon into two subtypes and then for a particular case eliminating one of those subtypes.
(C) offering a general principle and then demonstrating that the general principle is violated in this particular case.
(D) showing that two apparently mutually exclusive alternatives are actually compatible with each other.
(E) explaining the historical context of an incident in order to demonstrate that each of the two possible scenarios involving the incident is as likely as the other.

Answer B.

The argument proceeds by:

(B) Distinguishing a phenomenon into two subtypes and then, for a particular case, eliminating one of those subtypes.

In this argument, the phenomenon being discussed is the creation of nineteenth-century recordings of poetry. The argument distinguishes two subtypes of these recordings: private souvenirs of famous poets and publicity stunts with actors. It then eliminates one of these subtypes (publicity stunts with actors) by arguing that the voice in the recording is likely Walt Whitman's because the poem was never published, suggesting it may be a rare private souvenir.