Definition: 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'.
Input: Sentence 1: Bill brought his boy to the park to play. Sentence 2: Bill sat on a bench and read a newspaper. Sentence 3: When he looked up, to his terror, he couldn't see his child. Sentence 4: He looked around frantic for a moment before hearing his son's voice. Sentence 5: Bill's boy was underneath his bench, playing in the dirt. Choices: a. The Cottage Cheese. b. Lost Son.

b