Given the task definition and input, reply with output. 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: One day Tom decided to visit his friend. Sentence 2: When he got there he saw that the house was on fire. Sentence 3: He tried to get inside but the door was locked. Sentence 4: He then kicked it down inside he found his friend on the floor. Sentence 5: He was able to get him out and Tom saved his friend's life. Choices: a. Rescue. b. Lucky Number.
a