Answer:
The topic sentence is number 1: As exemplified throughout Fitzgerald's classic, The Great Gatsby, people and situations are not always what they seem.
Step-by-step explanation:
A topic sentence has the purpose of expressing the main idea of the paragraph in which it is inserted. In the paragraph we are analyzing here, the whole idea is to show how Fitzgerald's characters aren't always what they seem, since the ones we would expect to be happy and centered are the ones who are miserable and "messed up". The sentences that follow the topic sentence offer evidence of what the topic sentence states, having, thus, the objective of developing its idea.