Which of the following statements may not be true？ A．People break their large scale computer system

Which of the following statements may not be true？

A．People break their large scale computer systems up into smaller subsystems for security purposes.

B．Personal computers are most likely to be invaded by unauthorized persons.

C．All of the people invading computer systems are trying to spy or sabotage.

D．Some people penetrate into protected databanks in order to prove their technical worth.