Which choice completes the text so that it conforms to the conventions of Standard English? In ancient Greece, an Epicurean was a follower of Epicurus, a philosopher whose beliefs revolved around the pursuit of pleasure. Epicurus defined pleasure as 'the absence of pain in the body and of trouble in the ______blank that all life's virtues derived from this absence.

Choice A is the best answer. The convention being tested is punctuation use between a main clause and a participial phrase. This choice correctly uses a comma to mark the boundary between the main clause ('Epicurus…‘soul'') and the participial phrase ('positing…absence') that provides additional information about how Epicurus defined pleasure. Choice B is incorrect because a colon can't be used in this way to join a main clause and a participial phrase. Choice C is incorrect because a semicolon can't be used in this way to join a main clause and a participial phrase. Choice D is incorrect because it results in a rhetorically unacceptable sentence fragment beginning with 'positing.'