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: The Tube Slide. Sentence 1: Kurt loved waterslides. Sentence 2: The tube slide was his favorite! Sentence 3: He rode it dozens of times in one day. Sentence 4: He would stand in line for a long time just to ride again. Choices: a. They valued their online friendships a lot. b. The slide was fast and fun!
b