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: Cash Money App. Sentence 1: Ben created an app for cell phones. Sentence 2: The app tells you where the closest gas station is at all times. Sentence 3: Ben made the app free to the general public. Sentence 4: A company offered to buy Ben's app from him. Choices: a. Luckily, he was able to get on the bus at the last second. b. Ben sold his app and made lots of money.
b