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: Marvin decided to run a marathon. Sentence 2: He started running every day, and gradually increased his distance. Sentence 3: He thought he was ready to run his first marathon. Sentence 4: After running eighteen miles, Marvin had to rest. Sentence 5: He walked the rest of the way, but was pleased to finish the race. Choices: a. Hitting the Wall. b. Learning to Ride.

a