Given the task definition, example input & output, solve the new input case.
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'.
Example: Sentence 1: Marcus needed clothing for a business casual event. Sentence 2: All of his clothes were either too formal or too casual. Sentence 3: He decided to buy a pair of khakis. Sentence 4: The pair he bought fit him perfectly. Sentence 5: Marcus was happy to have the right clothes for the event. Choices: a. Marcus Buys Khakis. b. Marcus Works.
Output: a
Marcus's reasons for buying khakis is established, followed by his purchase of them and reaction.

New input case for you: Sentence 1: Ned has some mud on his feet from playing outside today. Sentence 2: He decides to clean his feet. Sentence 3: Ned gives both of his feet a thorough washing. Sentence 4: He feels much better afterwards. Sentence 5: Ned is happy he doesn't have muddy feet any longer. Choices: a. Ned Washes His Feet. b. Ann's Surprise Visit.
Output:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
a