Final answer:
Caspase-8 does not directly activate TNF. It activates downstream effector caspases and indirectly activates Bid and Bax through cleavage and pro-apoptotic stimuli, respectively.
Step-by-step explanation:
Caspase-8 is an initiator caspase that plays a crucial role in initiating the apoptosis pathway. It activates downstream effector caspases, such as caspase-3 and caspase-7, which execute the cell death process. However, caspase-8 does not directly activate Bid, Bax, or TNF. Bid is activated by caspase-8 through cleavage, leading to the release of a truncated form of Bid that promotes mitochondrial outer membrane permeabilization, while Bax is activated through multiple pro-apoptotic stimuli. TNF, on the other hand, activates an extrinsic apoptosis pathway through its receptor, but caspase-8 is involved downstream in this pathway, not directly activating TNF. Therefore, the correct answer is d) TNF.