In this task, you're given the title of a five-sentence story, the first four sentences, and two options for the fifth sentence as a and b. Your job is to pick the sentence option that seamlessly connects with the rest of the story, indicating your choice as 'a' or 'b'. If both sentences are plausible, pick the one that makes more sense.

Title: The Math Problem. Sentence 1: The teacher looked out over the class and Joey slid down in his seat. Sentence 2: One finger pointed in his direction and Joey slid from his desk. Sentence 3: He stared up at the jumble of numbers on the chalkboard. Sentence 4: He wrote an answer on the board and hurried to his desk. Choices: a. Many customers were very happy when seeing the product. b. After the teacher said the answer was right, Joey smiled.
b

Title: Love Gives Strength. Sentence 1: Michelle knew she wasn't going to win the track championship. Sentence 2: She'd made it to the finals, but she knew she wouldn't beat the star. Sentence 3: Michelle got in her starting block in her lane. Sentence 4: The supposedly fastest girl in track right next to her. Choices: a. He was trying to hide its brand, but gave up the habit after that. b. Michelle's mother cheered so loud Michelle pushed and won the race.
b

Title: Karate. Sentence 1: I've always wanted to take karate classes since I was a child. Sentence 2: So when I turned 35 years old I enrolled in a class. Sentence 3: To my surprise I was really good at karate. Sentence 4: I stuck with the classes for 3 years straight. Choices: a. I now have a black belt in karate. b. When the nurse brought out the needle, Joe promptly fainted!
a