The correct answer is (B) A person who takes advantage of circumstances (without concern for principle); someone who makes decisions or acts on the basis of expediency, regardless of honesty, fairness, justice, or morality; one who practices opportunism.

Opportunist comes from Latin opportunus (convenient).

Examples of use:

• Many corporation CEOs of recent years appear to have been opportunists.
• Many persons believe that the field of politics is filled with opportunists.