How does Wheel B turn in relation to Wheel D?

To understand how Wheel B turns in relation to Wheel D, it's important to consider the mechanics of how gears and wheels usually interact, especially in situations where they are aligned directly in gear configurations.

When two wheels are connected, the direction and speed of their rotations depend on how they’re meshed together. If Wheel B turns counter-clockwise, it implies that the teeth of Wheel B engage with the teeth of Wheel D in a way that would necessitate Wheel D to rotate in the opposite direction. Hence, if Wheel B is turning counter-clockwise, Wheel D would be forced to rotate clockwise due to this interaction.

The speed relationship involves the sizes of the wheels. If Wheel B is smaller than Wheel D, it will turn faster than D, due to the mechanics of gear ratios. However, if Wheel B is larger or of a similar size, it would turn slower. Given that the choice mentions that Wheel B turns slower than Wheel D, this indicates a specific scenario where Wheel B is either significantly larger or has a different mechanical advantage that results in slower rotation despite the counter-clockwise movement.

This analysis aligns with the understanding of gears and their interactions, confirming that Wheel B indeed turns counter-clockwise and at a slower speed compared to Wheel D.