Which is grammatically correct and why:
a. a one year contract
b. an one year contract.

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.

situational archetype describes the adventures of hero. the examples of situational archetypes are the quest, good vs evil, the task which represent respectively search, good forces, characters vs the evil ones and a certain job that must be done. from the given options, we cannot observe the subplot the beauty and the beast which is a correct answer for this question.