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: Susie took her cousin Kara to the museum. Sentence 2: She wanted to show Kara around. Sentence 3: But then Kara got lost. Sentence 4: So Suzy got scared. Sentence 5: She called Kara but there was no answer and Susy had to call 911. Choices: a. The Loan. b. Lost in the museum.
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
b