Correct Option: A

cunning (Adjective) : crafty; wily; clever and skilful
candid (Adjective) : saying what you think openly and honestly; not hiding your thoughts; frank and honest
diplomatic (Adjective) : connected with managing relations between countries; having or showing skill in dealing with people in difficult situations; tactful
doubtful (Adjective) : dubious; not sure; uncertain and feeling doubt
impertinent (Adjective) : impolite; rude and not showing respect