Final answer:
The camshaft controls the opening and closing of the cylinder head ports in an internal combustion engine, coordinating with lifters, push rods, and rocker arms to achieve proper engine valve timing. (Option A)
Step-by-step explanation:
The component that controls the opening and closing of the cylinder head ports in an internal combustion engine is the camshaft (Option A). The camshaft is equipped with cams (lobes) that press against the lifter or tappet, which in turn moves the push rod, and this subsequently moves the rocker's arm. As the camshaft rotates, its lobes come into contact with other valvetrain components such as lifters, push rods, rocker arms, and valves. The shape and arrangement of these lobes determine the timing and duration of the valve openings and closings, influencing the engine's performance characteristics.
The rocker's arm then opens and closes the intake and exhaust valves at the correct timing, allowing the engine to inhale air and fuel and exhale exhaust gases. B) Rocker arm, C) Push rod, and D) Lifter are all involved in the valve train, but it is the camshaft that directly determines the sequence of these events.