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 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.

Title: New Dog. Sentence 1: The kids had been begging for a dog. Sentence 2: Their parents were still unsure about the idea. Sentence 3: After weeks of begging, they finally gave in. Sentence 4: They took the kids to the animal shelter and let the pick out a dog. Choices: a. The dog became part of the family and the kids loved helping with it. b. Allison called her boss to say she couldn't go in.
a