Answer:
The correct option is : C. prevent the immune system from responding to self-antigens and D. prevent excessive response to foreign antigens
Step-by-step explanation:
Immune tolerance, also known as the immunotolerance, of the immune system, is a state of unresponsiveness to the cells or tissues that are capable of eliciting an immune response in an organism.
Tolerance is classified into central and peripheral. The central tolerance is induced in the thymus and bone marrow. Whereas, the peripheral tolerance is induced in the other tissues and the lymph nodes.
Central tolerance of the immune system is responsible for discriminating the self cells from the non-self cells of the body and thus prevents the body from responding to self-antigens.
Peripheral tolerance of the immune system is responsible for preventing excessive response of the immune system to foreign antigens like allergens.