quite an interesting way to teach topic sentences, because the answer to this question is the best definition of a topic sentence that one can present, it is as if answering the questions taught you how to do it, this is some real teaching, it is terribly well-done.
the topic sentence in this paragraph is:
topic sentences writers stay on track and keep a paragraph from becoming an aimless collection of sentences about an idea.
which incidentally tells you what a topic sentence should be.
i cannot see any of the options
true or false?...