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: Mark had lost his dog over a month ago. Sentence 2: He missed his dog very much. Sentence 3: One evening while mowing the lawn he notices something. Sentence 4: He sees a dog in the street that looked like his lost dog. Sentence 5: It turns out to be his lost dog who had returned home. Choices: a. Mark's dog returns. b. Lenny gets fired.

a