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: Nancy was jubilant when she came out of her boss' office. Sentence 2: She hopped and danced in front of her colleagues. Sentence 3: She finally brandished the crisp twenty thousand dollar check. Sentence 4: Everyone was flabbergasted. Sentence 5: As bonus went, this one took the cake. Choices: a. Bonus. b. The Lights.
a