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: The other day people had to use my bathroom. Sentence 2: I had forgotten to clean it. Sentence 3: I was rather horrified. Sentence 4: But they insisted they didn't mind. Sentence 5: But I felt badly they had to use it with all the dust so I cleaned it. Choices: a. Having to use a portable bathroom. b. Dusty bathroom.

b