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: Two children were playing near the beach one day building castles. Sentence 2: They were each trying to build one as fast as they could. Sentence 3: When the tide came in it washed away their castles, they were upset. Sentence 4: This didn't last for long because with the tide came a clam. Sentence 5: They checked inside to find a beautiful white pearl to their surprise. Choices: a. The Pearl. b. Jojo's lost puppy..
a