Given the task definition and input, reply with output. 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: Weight Loss. Sentence 1: One day, Mary realized that she had gained a lot of weight. Sentence 2: She made a plan for losing the extra pounds. Sentence 3: She began a lot of fruits and vegetables instead of unhealthy snacks. Sentence 4: She also walked a few miles every day. Choices: a. Cathy was glad to have the goldfish part of her family. b. Within a few months she was back to her healthy weight.
a