The correct answer is (C).
(C) Role of a Statement
Step 1: Identify the Question Type
Since the question provides a claim from the stimulus and asks for the "role played" by that claim, this is a Role of a Statement question. Start by locating the cited claim and making a mark next to it. Then dissect the argument into its conclusion and evidence, and consider where and how the marked claim fits into the argument.
Step 2: Untangle the Stimulus
The cited claim about jazz singers using their voices much as jazz players use horns is the very first sentence. The example of Billie Holiday, who used her voice exactly as described in the claim, follows next. After proposing another claim about a reciprocal effect (horn players mimicking vocal styles), the author reaches the conclusion (indicated by the Conclusion Keyword "[s]o"): Jazz contains mainly horns that sound like voices and voices that sound like horns.
Step 3: Make a Prediction
The example of Billie Holiday supports the statement in question. However, that statement is not the ultimate conclusion. The main conclusion, at the end, is supported by both the initial claim and the converse claim about horns emulating voices. So the correct answer will likely express the dual context of the opening claim: an example supports it, and it supports the final conclusion.
Step 4: Evaluate the Answer Choices
(C) accurately describes the role of the opening claim. Some evidence is provided for it (Billie Holiday), and it's used to support the main conclusion (jazz has voicelike horns and hornlike voices).
(A) distorts the argument's structure. The claim from the question stem is not the argument's main conclusion. Moreover, while the cited claim is supported by another statement (the example of Billie Holiday), that statement is not backed up by any other statement.
(B) is off base because the last sentence (as evidenced by the Keyword "[s]o") is also a conclusionÑin fact, it's the main one.
(D) goes astray immediately by suggesting there's no evidence for the opening claim. Even though there are no evidence Keywords, the information about Billie Holiday supports the idea that jazz singers use their voices like instruments.
(E) is Half Right, Half Wrong. The answer gets the first half right: The claim in question does support a conclusion. However, it supports the main conclusion. It is a subsidiary conclusion; it does not support one.
