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: Ben decided to start exercising every morning. Sentence 2: He was very diligent for about a week. Sentence 3: Slowly he started to slack off. Sentence 4: And he went back to his old routine. Sentence 5: He had to push himself to start exercising again. Choices: a. Old routine. b. The Pond.

a