What is the most compact representation of the following IPv6 address?

What is the most compact representation of the following IPv6 address?
2001:db8:0000:0000:cafe:0000:0000:1234

A.
2001:db8::cafe::1234

B.
2001:db8::cafe:0000:0000:1234

C.
2001:db8:0:0:cafe::1234

D.
2001:db8::cafe:0:1234

Explanation: