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 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: Dillan's Bad Grades. Sentence 1: Dillan had bad grades on his report card. Sentence 2: He didn't want his parents to find out. Sentence 3: Dillan hid the report card from his parents. Sentence 4: The teacher called his parents for a conference about his grades. Choices: a. Finally, he told his mom goodbye and walked to the bus stop. b. Dylan's parents realized that he was making bad grades.
a