Which of the following statements is true?
a complex sentences are concise.
b complex sentences have difficult vocabulary.
c complex sentences have many clauses.
d complex sentences ask the reader a question.

The true statement is:

C. Complex sentences have many clauses.

Explanation:

A complex sentence is a sentence which contains two or than two clauses. Among the clauses, there is one independent clause and at least one dependent clause. Option A is incorrect because simple sentences are concise. Option B is also incorrect. Option D is incorrect because sentences which ask a question is known as interrogatory sentences.

i think the answer is c.