Final answer:
PD-1 is the inhibitory receptor that prevents naive B cells from becoming activated, ensuring proper regulation of the immune response and prevention of autoimmunity. Option c.
Step-by-step explanation:
The inhibitory receptor that prevents naive B cells from becoming activated is c. PD-1 (Programmed cell death protein 1). PD-1 is an inhibitory receptor expressed on the surface of B cells (among other cells) which, when engaged, delivers a signal that suppresses the immune response, including the activation and proliferation of B cells.
This mechanism is important to prevent autoimmunity and to regulate the immune response, ensuring that it does not become overactive.
Options a. CD28, b. CD40, and d. BCR (B-cell receptor) are not typically considered inhibitory; rather, CD28 and CD40 are co-stimulatory molecules involved in the activation of T cells and B cells, respectively, while BCR is the receptor on B cells that recognizes specific antigens. Option c.