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: Rory began feeling sluggish after his thirtieth birthday. Sentence 2: It had been years since he'd played sports or worked out. Sentence 3: He got a new job across town. Sentence 4: To save money, he usually walked instead of taking the bus. Sentence 5: Getting so much exercise, he began to feel better. Choices: a. Out of Milk. b. Rory's Unplanned Workout.
b