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: Joe was a police officer. Sentence 2: Joe was patrolling the streets of the city in his cruiser. Sentence 3: Suddenly, Joe was alerted to a crime happening near him by dispatch. Sentence 4: Joe responded to the scene and found a bank robber fleeing on foot. Sentence 5: Joe arrested the criminal and was promoted. Choices: a. The Water Jug. b. Police Officer.
b