Check the Following Paragraphs for Unity

Check the following paragraphs for unity. Select the number of the sentence that does not belong in the paragraph. Identify the sentence that does not belong.
(1) In nineteenth-century America, chocolate was a rare, expensive treat. (2) It was Milton Hershey, founder of Hershey Foods, who made chocolate affordable and widely available. (3) He had built a successful caramel-making company before chocolate-making first fascinated him in 1893. (4) For years, he worked at perfecting a recipe for making milk chocolate, a process which up until then had been the secret of Swiss chocolate makers. (5) Hershey experimented with different combinations of milk, sugar, and cocoa until he found the right one. (6) Then, using mass-production techniques, he was able to make and sell large quantities of individually wrapped, affordably priced chocolate. (7) For decades after Hershey began manufacturing his Hershey bars in 1904, the candy cost only a nickel. (8) In the early 1900s, a nickel also bought a ride on the New York subway.

A) Sentence 6
B) Sentence 7
C) Sentence 8