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 authentication method in which a computer user is granted access only after successfully presenting two or more pieces of evidence (or factors) to an authentication mechanism: knowledge (something the user and only the user knows), possession (something the user and only the user has), and inherence (something the user and only the user is)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