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: My sister was expecting her first baby. Sentence 2: She was due around Christmas time. Sentence 3: We went up to visit at Christmas, hoping to see the baby too. Sentence 4: The baby took its own sweet time. Sentence 5: She was finally born, but not until January 5th! Choices: a. Baby. b. Black Out.
a