The camshaft in an overhead cam design is generally driven by which of the following?

In an overhead cam (OHC) design, the camshaft's function is to open and close the engine's valves at the correct times during the intake and exhaust strokes. The camshaft is typically driven by a timing chain or a timing belt. These components effectively synchronize the rotation of the camshaft with that of the crankshaft, ensuring that the timing of the valve events matches the position of the pistons.

Using a chain or belt provides a reliable method for this synchronization due to their strength and ability to handle the high-speed rotation involved in engine operation. Chains tend to be more durable and require less maintenance, while belts are often quieter and lighter but do require periodic replacement.

The other options suggest various configurations involving gears or sprockets, which are less common in OHC designs. While some engines do use gears for timing, the predominant methods in OHC systems are indeed timing chains or belts, making the first option the most suitable choice for describing how the camshaft is driven in this design.