Definition: 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'.
Input: Sentence 1: Tom and Chris were friends. Sentence 2: Chris liked doing Sudoku puzzles. Sentence 3: Tom had never heard of Sudoku. Sentence 4: Chris introduced Tom to Sudoku. Sentence 5: Tom found his new hobby and liked doing the puzzles. Choices: a. Sudoku. b. Speakers.

a