Instructions: 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.
Input: Title: Radio Change. Sentence 1: John was driving to work while listening to the radio. Sentence 2: But he couldn't find a song he liked. Sentence 3: He kept switching stations. Sentence 4: He finally found a song he liked. Choices: a. But by that time, he was already at work. b. He caught a fish.
Output:
a