What are two rules for compacting IPv6 addresses？（）

A. The maximum number of times a double colon can replace a 16-bit segment that consists of all zeroes is two
B. The leading zeroes in any 16-bit segment do not have to be written.
C. Every 16-bit segment that consists of all zeroes can be represented with a single colon
D. The trailing zeroes in any 16-bit segment do not have to be written.
E. Any single， continuous string of one or more 16-bit segments that consists of all zeroes can be represented with a double colon
F. Two zeroes in the middle of any 16-bit segment do not have to be writte