Select the sentence that would best appear in the beginning of a narrative.
a) my experience with my dog has taught me to never give up hope.
b) it was my birthday, and i was hoping that my wish for a dog would come true.
c) on my way home, i found a lonely and hungry-looking dog roaming the neighborhood.
d) i posted flyers around the neighborhood, but no one called to claim the dog.

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.

the answer is industry