Which is the compressed format of the IPv6 address 2001:0db8:0000:0000:0ab8:0001:0000:1000?

To compress the IPv6 address 2001:0db8:0000:0000:0ab8:0001:0000:1000, we follow the standard rules for IPv6 address compression:

1. Omit leading zeros in each 16-bit block.
2. Replace one or more consecutive blocks of zeros with a double colon (::), but this can only be done once in the address.

Applying these rules, the compressed format of the IPv6 address is:

2001:db8::ab8:1:0:1000

Explanation of the options:

1. 2001:db8::ab8:1:0:1000: Correct. It correctly omits leading zeros and collapses the consecutive blocks of zeros into a double colon.
2. 2001:db8::a0b0:8:1: Incorrect. This changes the values in the original address, which is not a correct representation.
3. 2001:db8:1::ab8:0:1: Incorrect. This option alters the structure and values of the original address.
4. 2001:db8:0:1::8:1: Incorrect. This option also changes the structure and values of the original address.

Therefore, the first option, 2001:db8::ab8:1:0:1000, is the correctly compressed format of the given IPv6 address.