Final answer:
Bcl-2 is the molecule that inhibits Caspase 3 and 9 by preventing the release of cytochrome c and thereby hindering the caspase cascade involved in apoptosis. The correct option is B.
Step-by-step explanation:
The molecule that inhibits Caspase 3 and 9 is Bcl-2. Caspases are a family of protease enzymes playing essential roles in programmed cell death (apoptosis).
Bcl-2 is known for its role in regulating apoptosis by preventing the release of cytochrome c from mitochondria, thus inhibiting the initiation of the caspase cascade that includes both Caspase 9 and Caspase 3. p53 is a tumor suppressor protein that can mediate cell cycle control and trigger apoptosis but does not directly inhibit the caspases.
However, its regulatory functions can indirectly influence the apoptotic pathway. NF-κB, when activated, can stimulate transcription and promote cell survival, and Cytochrome c is actually part of the apoptosome complex that activates Caspase 9 leading to cell apoptosis.