Answer:
Option (C).
Explanation:
Adaptive immunity or acquired immunity can be defined as a type of immunity. The cells, which are involved in adaptive immune responses include T cells and B cells (collectively known as lymphocytes).
It is known as acquired immunity because it is developed by activation of T cells and B cells after getting exposure with antigens as from natural pathogens or vaccines. The activated cells then provide response against the pathogens by producing antibodies and cytokines.
Thus, the correct answer is option (C).