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: Sarah was angry at her girlfriend. Sentence 2: She suspected that her girlfriend might be cheating on her. Sentence 3: She decided to follow her girlfriend after she went out. Sentence 4: Sarah's girlfriend just wandered around the neighborhood aimlessly. Sentence 5: It turned out that her girlfriend had just been playing Pokemon Go! Choices: a. Sarah's Girlfriend. b. New Lights.

a