You will be given a definition of a task first, then some input of the task.
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: Halloween Costume. Sentence 1: Dan was deliberating what to wear for Halloween this year. Sentence 2: Dan decided he would go as Mario, and his brother as Luigi. Sentence 3: In addition, Dan would dress his son up as Yoshi as well. Sentence 4: Dan was surprised to see his nephew dressed as Bowser. Choices: a. Dan loved the costumes that they decided to wear for Halloween. b. Unfortunately, Dan was heartbroken to find out it was already sold.
Output:
b