What are two rules for compacting IPv6 addresses？（）
- AThe maximum number of times a double colon can replace a 16-bit segment that consists of all zeroes is two
- BThe leading zeroes in any 16-bit segment do not have to be written.
- CEvery 16-bit segment that consists of all zeroes can be represented with a single colon
- DThe trailing zeroes in any 16-bit segment do not have to be written.
- EAny single， continuous string of one or more 16-bit segments that consists of all zeroes can be represented with a double colon
- FTwo zeroes in the middle of any 16-bit segment do not have to be writte