You will be given a definition of a task first, then some input of the task.
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 does not connect with the rest of the story, indicating your choice as 'a' or 'b'. If both sentences are plausible, pick the one that makes less sense.

Title: Ryan Writes A Letter. Sentence 1: Ryan decides he would like to contact an old friend. Sentence 2: He writes his friend a long letter. Sentence 3: He sends his friend the letter in the mail. Sentence 4: His friend receives it later that week. Choices: a. Ryan is happy he contacted his friend. b. Carlos was happy that he had spent the day on the water.
Output:
b