Answer:
The correct answer is d. plasma membrane
Step-by-step explanation:
Bacteria do not have membrane-enclosed organelle like mitochondria to generate ATP but even then it produces ATP because in bacterial plasma membrane acts as the machinery of ATP synthesis.
The ATP synthesis in bacteria is the same as eukaryotes. In prokaryotes, the plasma membrane consists of an electron transport system and NADH helps in building the proton gradient across the plasma membrane.
Then after the proton gradient is built in the plasma membrane the proton tends to come back into the cytoplasm through the ATP synthase complex which generates ATP from ADP and inorganic phosphate.
Therefore the correct answer is d. plasma membrane.