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: Jack and The Puppy. Sentence 1: Jack was a nice friendly little boy. Sentence 2: He had a little black puppy names Bunny. Sentence 3: Jack and Bunny loved to play outside in the sunshine. Sentence 4: One day Bunny ran away and Jack could not find him. Choices: a. But the teacher refused to accept it. b. Jack searched for Bunny, and when we finally found him he was so happy.
b