What is the cipher type?

A ____________cipher basically means it is using a fixed key which replaces the message

with a pseudorandom string of characters.

It is basically the encryption of each letter one at a time.

What is the cipher type?
A . Stream
B . Block
C . Parallel
D . RSA

Answer: A

Explanation:

Stream cipher basically means using a fixed key which replaces the message with a pseudorandom string of characters. It is basically the encryption of each letter one at a time.