For an organization considering two-factor authentication for secure network access, which of the
following is MOST secure?
A.
Challenge response and private key
B.
Digital certificates and Single Sign-On (SSO)
C.
Tokens and passphrase
D.
Smart card and biometrics
C is the right answer (something you have , something you know)
D both are something you have
Ans D is something you have and something you are. Smart card is something you have and Biometrics is something you are like fingerprint retina scan etc
Biometric is something you Are, And its most strongest Single factor. In that case, if you have to choose between Choice C and D, D will be the answer. The strongest combination of all.