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: All About a Boy. Sentence 1: Rachael and Kristy were best friends. Sentence 2: Rachael was dating a boy named Mark. Sentence 3: Mark broke up with Rachel for no reason. Sentence 4: The next week Mark and Kristy started dating. Choices: a. Impatient Agnes ended up waiting much longer than ten minutes. b. Rachael and Kristy are no longer best friends.
b