You will be given a definition of a task first, then some input of the task.
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: Cara finds her watch.. Sentence 1: Cara lost her watch during a family reunion. Sentence 2: She asked her brother for his help finding it. Sentence 3: Her brother brought over a metal detector since the watch was metal. Sentence 4: The metal detector went beep, beep, beep. Choices: a. Cara was so happy to have her watch back. b. He filled up his car.
Output:
a