The correct answer is C. comprises.

Explanation: The verb "comprises" means "to consist of" or "to be made up of." In this context, it indicates that the congregation includes all sorts and conditions of men.

Here's a breakdown of the other options:
- A. composes: This verb is used in the form "composes" (e.g., "The choir composes of ten singers.") but not in the sense of describing what something is made up of.
- B. consists: This verb is used with "of" (e.g., "The congregation consists of all sorts and conditions of men.") but does not fit grammatically in the given sentence.
- D. conjectures: This verb means "to form an opinion or theory without sufficient evidence," which does not fit the context of the sentence.