What is the maximum allowable key size of the Rijndael encryption algorithm?

A.
128 bits

B.
192 bits

C.
256 bits

D.
512 bits

Explanation:
AES, which Rijndael was designed for, is a symmetric block cipher that supports key sizes of 128, 192, and 256
bits. 256 bits is the maximum key size.
Incorrect Answers:
A, B: 128 bit and 192 bit keys are supported, but it is not the maximum.
D: Rijndael does not support 512 bit keys.

Harris, Shon, All In One CISSP Exam Guide, 6th Edition, McGraw-Hill, 2013, p. 809