Given the task definition and input, reply with output. 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'.

Sentence 1: My little sister wanted to catch a butterfly for a pet. Sentence 2: She had no idea what she was doing. Sentence 3: I helped her build a net and showed her where to look. Sentence 4: My little sister started swinging her net at the butterflies. Sentence 5: Eventually she caught one. Choices: a. Ian breaks his car. b. How to catch a butterfly.
b