The correct answer is (C) keen perception; acuteness of judgement and understanding; insight; perception; penetration. Also, the act, or instance, of discerning.

Discernment comes from Middle French discernement, discerner, Latin discernere (to separate).

Examples of use:

• He believed that she was a woman of unusual discernment.
• His experience and discernment helped him to read the character of others.