Which set of action satisfy the requirement for multi-factor authentication?

Which set of action satisfy the requirement for multi-factor authentication?
A . The user swipes a key fob, then clicks through an email link
B . The user enters a user name and password, and then clicks a notification in an authentication app on a mobile device
C . The user enters a PIN into an RSA token, and then enters the displayed RSA key on a login scre
D . The user enters a user name and password and then re-enters the credentials on a second screen

Answer: B