Correct option is B
A single-acting cylinder uses fluid pressure only in one direction (usually extension). For the return stroke, it depends on either a spring mechanism or an external load.
This is a key difference from double-acting cylinders, which use fluid pressure in both directions. Without a spring or load, the piston would not return to its original position.
Other components like valves control flow but do not provide return force. Therefore, the essential element for return motion is a spring or external force
