What are the valid types of one time password generator?

A.
All of the choices.

B.
Transaction synchronous

C.
Synchronous/PIN synchronous

D.
Asynchronous/PIN asynchronous

Explanation:
One-time Passwords are changed after every use. Handheld password generator (tokens) 3 basic
types: Synchronous/PIN synchronous, Transaction synchronous, Asynchronous/PIN asynchronous.