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: My brother injured his knee at practice. Sentence 2: We had to take him to the doctor. Sentence 3: The doctor examined his knee. Sentence 4: He made him try to bend it. Sentence 5: The doctor gave my brother a knee brace. Choices: a. Knee brace. b. Math homework.
a