Carson has been very stressed while pulling numerous all-nighters to complete his final exams and papers. He comes down with the flu the very next day after his last exam. What is a likely reason for his illness?
A. His stress hormones activated his lymphocytes.
B. His stress hormones suppressed the activity of his lymphocytes.
C. His anxiety level was not severe enough to trigger his lymphocytes.
D. His anxiety level was too severe to trigger his lymphocytes.

The correct answer is option B.

Explanation:

The immune system found within a human being comprises millions of cells that circulate all through the body with the help of blood. These cells help the body to fight against foreign invasions like viruses, bacteria, and other pathogens. The immune cells that primarily fight against the invasions are the white blood cells, which are further differentiated into phagocytes and lymphocytes.  

However, at the time of stress, the immune system loses the tendency to fight against the foreign invasions or the antigens, and thus, the person becomes more vulnerable to infections. At the time of stress, a hormone gets discharged known as a corticosteroid that diminishes the efficacy of the immune system, that is, by reducing the concentration of lymphocytes. Hence, option B is correct.  

c is the correct answer!