Final answer:
The correct answer is A. humoral immunity. B lymphocytes, or B cells, are responsible for the production of antibodies called immunoglobulins and are involved in the body's defense against pathogens and toxins in the extracellular environment.
Step-by-step explanation:
The correct answer is A. humoral immunity. The term 'humoral immunity' refers to mechanisms of the adaptive immune defenses that are mediated by B lymphocytes, or B cells. B cells are responsible for the production of antibodies called immunoglobulins, which are involved in the body's defense against pathogens and toxins in the extracellular environment. This process is referred to as humoral immunity.