In this task, you're given the title of a five-sentence story, the first four sentences, and two options for the fifth sentence as a and b. Your job is to pick the sentence option that seamlessly connects with the rest of the story, indicating your choice as 'a' or 'b'. If both sentences are plausible, pick the one that makes more sense.

Title: train tracks. Sentence 1: When Jimmy was little he always wondered where the train tracks went. Sentence 2: One day he started out on a quest to find his answer. Sentence 3: He walked for around an hour down the tracks. Sentence 4: They seemed to go on for ever and he decided to head back home. Choices: a. Jimmy is know convinced the train tracks go clear around the world. b. Then he tried soy milk and learned he liked it more than regular milk.
a