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.
People in this pandemic have lots on their mind these days. Causing people to stress, using stress management can give you ways to not feel it as often. People take it because they have more things to do and to pay for and that can really get to you at times. So having stress management classes can help clear your mind and be better.
The answer that sounds most correct would be: B) Open back and sufficient tread.