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: Tom wanted to go swimming. Sentence 2: There was a river near by. Sentence 3: Tom checked the news. Sentence 4: They said that the river was too polluted to swim in. Sentence 5: Tom decided against it. Choices: a. Pictures. b. Dirty River Water.

b