Which of the Following Is an Example of Design Principle

Which of the following is an example of design principle?

A) The interface of a computer system should help maintain consistent interaction with users;
B) A computer system should be able to provide users with control over the human-computer interaction;
C) Metaphors should be used properly in system design to enhance the cognitive fit;
D) If possible, direct manipulation should be enabled in a computer system to make users' operations easier;
E) A computer system should be able to support diverse users.