Really, none of these answers are good. leukocytes are the body's general immune cell, and lymphocytes are a type of leukocyte. Antibodies are only used when fighting an infection that your body already has experience with, so I'm guessing it you have to pick from these answers, its "lymphocytes", but it's not really the best answer.
Answer:
well first don't look down 2nd have a great day I'm not much of a therapist but when life gives you lemons you make lemonade