Concept:Hostility means unfriendly or aggressive behaviour, so we need its opposite.Explanation:"Hostility" is the opposite of "friendliness."A. faithfulness — being loyal, not the opposite.B. attitude — a general way of thinking or feeling, not the opposite.C. manner — a way of behaving, not the opposite.D. friendliness — being kind and welcoming, the direct opposite of hostility.Answer:D. friendliness