The Advanced Encryption Standard (Rijndael) block cipher
requirements regarding keys and block sizes have now evolved to
which configuration?

A.
Both the key and block sizes can be 128, 192, and 256 bits each.

B.
The block size is 128 bits, and the key size is 128 bits.

C.
The key size is 128 bits, and the block size can be 128, 192, or 256 bits.

D.
The block size is 128 bits, and the key can be 128, 192, or 256 bits.

Explanation:
AES is comprised of the three key sizes, 128, 192, and 256 bits with
a fixed block size of 128 bits. The Advanced Encryption Standard
(AES) was announced on November 26, 2001 , as Federal Information
Processing Standard Publication (FIPS PUB 197). FIPS PUB 197 states
that This standard may be used by Federal departments and agencies
when an agency determines that sensitive (unclassified) information
(as defined in P.L. 100-235) requires cryptographic protection.
Other FIPS-approved cryptographic algorithms may be used in addition
to, or in lieu of, this standard. Depending upon which of the
three keys is used, the standard may be referred to as AES-128,
AES-192 or AES-256.
The number of rounds used in the Rijndael cipher is a function of
the key size as follows:
256-bit key 14 rounds
192-bit key 12 rounds
128-bit key 10 rounds
Rijndael has a symmetric and parallel structure that provides for
flexibility of implementation and resistance to cryptanalytic attacks.
Attacks on Rijndael would involve the use of differential and linear
cryptanalysis.