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: Power cut. Sentence 1: It was an incredibly hot summer's day. Sentence 2: The Smith family was sat at home enjoying the air conditioning. Sentence 3: Suddenly the power cut out and the air conditioning shut off! Sentence 4: The house got so hot the whole family had to go to a friend's house. Choices: a. Zach was so proud of himself! b. Luckily when they returned the power was on and it was cool again.
a