Final answer:
The protein that promotes apoptosis by binding to and inactivating the Bcl2 protein is Bax. Option C.
Step-by-step explanation:
The protein that promotes apoptosis by binding to and inactivating the Bcl2 protein is Bax. Bax is a member of the Bcl2 protein family and acts as a proapoptotic protein. It promotes apoptosis by forming pores in the mitochondria, releasing cytochrome c, and triggering the activation of caspases.
Bax binds to the antiapoptotic protein Bcl2, preventing Bcl2 from inhibiting apoptosis. This leads to the activation of downstream apoptotic pathways, ultimately resulting in cell death.
Thus, option c. Bax is the correct answer.