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: The man turned on the heat. Sentence 2: The furnace did not heat up. Sentence 3: He called the maintenance man. Sentence 4: The maintenance man made it a priority. Sentence 5: The furnace was repaired that night. Choices: a. furnace. b. Seven.
a