Definition: 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'.
Input: Sentence 1: Allie and her friends got together. Sentence 2: They decided to have a gift exchange. Sentence 3: They spent very little. Sentence 4: When Allie liked her present, her friend was happy. Sentence 5: Allie was glad they had this. Choices: a. Present exchange. b. The rainbow.

a