Read the following paragraph and identify the topic sentence. (1) Everyone has heard of accounts, salespeople, and lawyers. (2) But have you ever heard of a kiss mixer or a belly builder? (3) Most jobs have common titles, but there are also many unusual position titles. (4) A kiss mixer, for instance, is the person who mixes the ingredients for candy kisses. (5) And a belly builder is the individual who assembles and fits the inside parts of pianos. Which sentence is the topic sentence?