Which arrow correctly shows the direction of pacific plate motion over
the stationary hotspot?

Northwest

Explanation:

The stationary hot spot, at present, is located at the central part of the northern half of the Pacific tectonic plate. The Pacific plate is moving on top of the hot spot, while it remains at the same location. The movement of the Pacific plate in relation to the hot spot is in northwestern direction.

This hot spot has been created by a mantle plum, which are parts of the upper mantle layer that have much higher activity, thus higher temperatures and pressure. This results in the magma being able to penetrate through the crust of the tectonic plates, not like in most of the cases where it manages to reach the surface only at the plate boundaries.

Because the plate is moving and the hot spot is stationary, over time it has created a volcanic island arc, known as the Hawaii Islands. The islands too provide good evidence about the direction of the movement of the Pacific plate, as they too are aligned from northwest (the oldest) to southeast (the youngest) direction.