How does oceanic crust move along mid-ocean ridges?
away from dense crust
parallel to the ridge
away from the ridge
under less dense crust

away from the ridge

Explanation:

The mid-ocean ridge is formed on the divergent plate boundary. Here the magma from the mantle manages to penetrate to the surface, and as it does, cools off quickly, and creates new crust. With the constant creation of new crust, the old crust is pushed away from the newly created one. The old crust gradually is pushed further and further away from the ocean ridge, while new crust is constantly pilling up at the mid-ocean ridge. Eventually this will lead to the old crust being pushed to a convergent plate boundary where it will be subducted and melted.