Questions 1 to 3 are based on the following conversation. At the end of the conversation, you will be given 15 seconds to answer the questions. Now, listen to the conversation.
According to this conversation, what was the "stupid mistake"
A．The student forgot to hand in his term paper because he was overtired and stressed.
B．The student handed in the earlier draft paper instead of the final edited paper.
C．The student missed the time to apply to grad school.
D．The student found the mistake of the mark on his paper.
