List of top Computer Science Questions on Network Security asked in Common University Entrance Test

Which of the following is/are false ?
(A) Computer viruses are healthy codes written to test the security health of a system 
(B) A worm is self replication of a program 
(C) Trojan horse is a utility program that does harm when its date is expired 
(D) Spyware is a healthy software which keeps an eye on activities happening on your computer 
Choose the correct answer from the options given below :