Final answer:
A rubber gasket is the only suitable material for maintaining a seal between an oxygen cylinder and a regulator, as it ensures a safe, pressure-resistant, and leakage-free connection.
Step-by-step explanation:
The only acceptable material for maintaining a seal between an oxygen cylinder and regulator is a rubber gasket. Materials such as duct tape, plastic wrap, and aluminum foil are not suitable for this purpose as they cannot ensure a safe and leak-free connection essential in medical and industrial applications where oxygen cylinders are used.
Rubber gaskets are specifically designed to withstand the pressure and properties of oxygen gas, providing a secure seal that prevents any oxygen leakage.