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 does not connect with the rest of the story, indicating your choice as 'a' or 'b'. If both sentences are plausible, pick the one that makes less sense.

Title: Walk. Sentence 1: Both Bob and Mike wanted to lose weight. Sentence 2: So they decided they should start to eat healthier. Sentence 3: But they also realized they needed to burn more calories. Sentence 4: So each night they decided to go for a long walk. Choices: a. His mother was so upset he never went back to that house again. b. They soon shed all the weight they needed to lose.
a