Final answer:
The processes that require direct ATP usage are the cocking and releasing of the myosin head, the activity of the Na+/K+ pump, and the Ca2+ pumps in the SR membrane. The correct answer is 'd', corresponding to options 1, 5, and 6.
Step-by-step explanation:
The processes that directly require ATP (adenosine triphosphate) to occur among the given options are:
Cocking of the myosin head, which involves the attachment of ATP to the myosin, and its subsequent hydrolysis which energizes the myosin heads.
Na+/K+ Pump activity, where ATP is used to transport sodium and potassium ions across the plasma membrane, maintaining the electrochemical gradient.
Releasing the myosin head from actin, because ATP must bind to the myosin head to release it from actin after contraction.
Ca2+ pumps in the SR (sarcoplasmic reticulum) membrane, which actively transport calcium ions back into the SR using energy from ATP.
The other options given (Release of acetylcholine and Removal of tropomyosin blockade) do not directly use ATP.
Therefore, the correct answer is option 'd', which covers the processes of Ca2+ pumps in SR membrane (1), Na+/K+ Pump activity (5), and Releasing myosin head from actin (6).