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: Lisa saw herself in the mirror. Sentence 2: She couldn't believe it. Sentence 3: She was going grey. Sentence 4: Lisa thought she was far too young. Sentence 5: She immediately shaved it off. Choices: a. Dog walking. b. Going grey.

b