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: The Tree. Sentence 1: The family loved Christmas. Sentence 2: They always picked out the perfect Christmas tree. Sentence 3: This year, they found one that was very tall and full. Sentence 4: They took it home and decorated it carefully. Choices: a. Unfortunately it was gone before he knew it. b. When it was all lit up, they stood back to admire it.
Output:
a