What cause and effect relationship do you see in the
underlined passage from
Section 1 of Mark
Twain's"The Invalid's Story"?
A. His condition and marital status caused
him many sufferings.
B. His age and marital status caused him
to look old and tired.
C. His condition and sufferings caused him
to look old and married.

a) walter looks unhealthy

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.