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 Whitehead family went to the zoo. Sentence 2: They packed a picnic lunch to take with them. Sentence 3: They parked a long way away so it didn't cost anything extra. Sentence 4: In the zoo the kids were mesmerized by it all. Sentence 5: Their favorite part was the penguin exhibit. Choices: a. Zoo. b. Shoes.
a