What is the difference between policing and shaping?

A.	Policing: Transmit and mark, then transmit the packets. Shaping: Buffer the exceeding packets.
B.	Policing: Transmit the packets. Shaping: Buffer the exceeding packets.
C.	Policing: Transmit, drop or mark, then transmit the packets. Shaping: Buffer the exceeding packets.
D.	Policing: Buffer the exceeding packets. Shaping: Transmit and mark, then transmit the packets.