Answer Description
While all answers are methods of authentication, a shared secret would not count in this instance. This is due to the fact that the knowledge portion of multifactor authentication is already covered by the use of a password and would not count towards being an MFA mechanism. MFA is requires at least two of the following: something you know, something you have or something you are.
Wikipedia
Multi-factor authentication is an electronic authentication method in which a computer user is granted access to a website or application only after successfully presenting two or more pieces of evidence (or factors) to an authentication mechanism: knowledge (something only the user knows), possession (something only the user has), and inherence (something only the user is) It protects the user from an unknown person trying to access their data such as personal ID details or financial assets Two-factor authentication (also known as 2FA) is a type, or subset, of multi-factor authentication It is a method of confirming users' claimed identities by using a combination of two different factors: 1) something they know, 2) something they have, or 3) something they are
Multi-factor_authentication - Wikipedia, the free encyclopedia