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: The Sofa. Sentence 1: Andrew beared the weight of the sofa. Sentence 2: His father carried the other end, and they walked into the house. Sentence 3: They were halfway up the stairs when Andrew could take no more. Sentence 4: He sat the sofa down for a brief rest. Choices: a. He scraped the sting with a credit card to help stop the stinging. b. Holding all the weight now, Andrew's father fell down the stairs.
a