What is the definition of "stream cipher"?

Group of answer choices

Cryptography wherein two keys are used, one to encrypt the message and another to decrypt it

A form of cryptography that encrypts the data as a stream, one bit at a time

A cryptographic method in which someone chooses a number by which to shift each letter of a text in the alphabet and substitute the new letter for the letter being encrypted

A method other than brute force to derive a cryptographic key