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: Mommy Karate. Sentence 1: Once there was a mom who was practicing Karate. Sentence 2: She went to class a few times each week. Sentence 3: She worked so hard she was able to earn her yellow belt. Sentence 4: Once she had her yellow belt she got to brag to her children. Choices: a. Doing Karate made her happy and strong! b. He was never seen again.
a