Definition: 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 does not connect with the rest of the story, indicating your choice as 'a' or 'b'. If both sentences are plausible, pick the one that makes less sense.
Input: Title: Tire Swings. Sentence 1: Matthew's front yard had a single tree in it. Sentence 2: He decided to make his son a swing. Sentence 3: His grandpa did the same for him when he was that age. Sentence 4: He threw a rope over a branch and tied an old tire to it. Choices: a. Then she left for school. b. His son swung for hours just like he did when he was a kid.
Output:
a