Which of the following can be considered as illegal or unethical in the context of information technology?

(A) A hospital reveals clinical history of a patient without the consent of a patient.

(B) A student using proprietary software without having license.

(C) A person stealing another person's credit card number.

(D) A college using Linux operating system (being an open-source software) on all its 200 computers on the campus.

Choose the correct answer from the options given below :