Speaker A: I wonder what's happened to Jer

问题：

Speaker A: I wonder what's happened to Jerry. He hasn't been around for at least two weeks.Speaker B: ______

A．Yes, two weeks halve passed before you know where you are.

B．Jerry is quite introvert. He doesn't like to let others know much about him.

C．Do you know the reason for his absence

D．He took a leave to see his mother in Europe.