Which of the following ciphers uses a polyalphabetic substitution process?

A.
Caesar cipher

B.
Simple substitution

C.
Vigenere

D.
ATBASH

Explanation:
Vigenere is a polyalphabetic substitution cipher created by Blaise de
Vigenere in the 16th century. Polyalphabetic substitution uses multiple alphabets
which makes the algorithm more immune to frequency analysis attacks.