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: Tony's car had started using water. Sentence 2: He discovered his radiator had a small hole in it. Sentence 3: His girlfriend suggested he buy another immediately. Sentence 4: Although he could afford to, Tony chose not to. Sentence 5: On his way home from work,Tony's engine ran hot and overheated. Choices: a. Lisa's Best Friend. b. Always Listen.
b