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.

Ex Input:
Title: Murder Mystery. Sentence 1: We went to a dinner and show one night. Sentence 2: There was a murder mystery on stage. Sentence 3: Someone was killed, and we had to solve the murder. Sentence 4: It was very entertaining. Choices: a. He is getting extra exercise. b. My son guessed the murderer correctly, and our meal was free.

Ex Output:
b

Ex Input:
Title: Sting. Sentence 1: Karen got stung by a bee. Sentence 2: Her arm swelled up immediately. Sentence 3: It turned out she was allergic to bees! Sentence 4: She had to go to the hospital for medication. Choices: a. Then she felt much better better! b. Tim and the friend stopped talking afterward.

Ex Output:
a

Ex Input:
Title: The bird flies. Sentence 1: Today I saw a baby bird. Sentence 2: The bird was in a tree. Sentence 3: The mother bird was teaching the baby bird. Sentence 4: She dropped the bird out of the nest. Choices: a. The baby bird flew away. b. The cake was covered in ash and looked like a mess!

Ex Output:
a