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 seamlessly connects with the rest of the story, indicating your choice as 'a' or 'b'. If both sentences are plausible, pick the one that makes more sense.
Q: Title: Allergy Outbreak. Sentence 1: My siblings and I visited my grandfather's house. Sentence 2: Since today was his birthday, we threw a celebration. Sentence 3: Unfortunately, I caught a bad allergy and started coughing. Sentence 4: When I came home, the allergy grew worse. Choices: a. In addition, he tried to go to sleep for the remainder of the ride. b. Before going to bed, I had to take allergy tablets.
A:
b