Given the task definition and input, reply with output. In this task, you're given five sentences, numbered 1 through 5, and two options a and b for possible titles for the story. Your job is to choose the title that better fits the story. Indicate your choice by 'a' or 'b'.

Sentence 1: The fly landed on the wall. Sentence 2: The man tried to hit it. Sentence 3: The fly got away. Sentence 4: The man woke up his son. Sentence 5: His son got the fly. Choices: a. Bill's Antique Shop. b. Fly.
b