Which of the following statements would NOT be a proper definition for a Trojan Horse?

Which of the following statements would NOT be a proper definition for a Trojan Horse?

A.
An authorized program that has been designed to capture keyboard keystroke while the user is
unaware of such activity being performed

B.
An unauthorized program contained within a legitimate program. This unauthorized program
performs functions unknown (and probably unwanted) by the user

C.
A legitimate program that has been altered by the placement of unauthorized code within it; this
code performs functions unknown (and probably unwanted) by the user

D.
Any program that appears to perform a desirable and necessary function but that (because of
unauthorized code within it that is unknown to the user) performs functions unknown (and
definitely unwanted) by the user