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: I waited near my class before 10 minutes before it started. Sentence 2: When I placed my water bottle in my bag, the cap fell loose. Sentence 3: Some water soaked my lab notebook and other papers. Sentence 4: I quickly took it out. Sentence 5: Since my lab notebook was ruined, I had to throw it away. Choices: a. Breaking up. b. Bad Luck in an Instant.
b