Unspecified a. typical IPv6 prefix used to indicate the network portion of the address. /64 b. IPv6 address represented as ::/128 (compressed form) and cannot be assigned to an interface Unique local c. Unique, internet-routable IPv6 address (dynamic or static) Loopback d. Used to communicate with other devices only on the same IPv6 subnet.

The answer to this question can be defined as follows:

Explanation:

In the given statements there are some mistype errors so, in the explanation section, we define the question with their suitable answer.

In choice A:

The Internet Protocol version 6 (IPv6) Prefix Length is being used to identify however many bits are already in the network part of its Global Unicast IPv6 address. It uses the number 64 for employed to recognize the network part of the very first 64 bits, that's why in Option A answer is "/64".

In choice B:

An IP address is used to represent 8 classes, in which each representing 16 bits, in the representation IP address it uses:: that is unspecified, that's why in Option B answer is "Unspecified".

In choice C:

The global unicast is a single connection on each sender and receiver, it specified from each network address, through one position upon its network to the other, that's why in Option C answer is "global unicast".

In choice D:

The link-local is used to communicate with other devices with the same IPv6 subnet, that's why in Option D answer is "link-local".

Please find the attachment of the question:

which functions return a valid value without any arguments?

(-blank- and -blank- return a valid value without any arguments.)

1st -blank-

today

sqrt

count

2nd -blank-

round

now

sqrt