Explanation/Reference:
Explanation:
Authentication systems or methods are based on one or more of these five factors:
Something you know, such as a password or PIN

Something you have, such as a smart card, token, or identification device

Something you are, such as your fingerprints or retinal pattern (often called biometrics)

Something you do, such as an action you must take to complete authentication

Somewhere you are (this is based on geolocation)

Multifactor authentication is authentication that uses two of more of the authentication factors listed above.
In this question, we can use voice recognition (something you are) and a one-time PIN token (something you have) to provide two factors of authentication. The one-time PIN token is a small device that generates a one-time PIN to enable access.