Answer:
The correct answer is B. May involve enhancement or impairment of the immune system.
Explanation:
Stress for a shorter time period can be lead to an enhancement of the immune system as it increases the essential alert system of the body and regulates it.
However, stress for a longer period reduces the ability of the immune system to fight with antigens that can lead to infection and suppressing of the lymphocytes.
Thus, the correct answer is B.
