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: Every morning, Jill sneezed and coughed. Sentence 2: But she didn't know what caused it. Sentence 3: She cleaned up everything in her house. Sentence 4: But it didn't go away. Sentence 5: After buying an air purifier, however, her problems went away. Choices: a. Clean Air. b. Fast.

a