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: Total exhaustion. Sentence 1: Last night I tried cramming for a test. Sentence 2: It was midnight and I was try to get work done. Sentence 3: Unfortunately my eyes started closing. Sentence 4: I was exhausted. Choices: a. Now Tina could have all the yogurt she wanted. b. When i woke up I was very unprepared.
b