Which feature do you usually see when tectonic plates move apart?

A. mountains

B. volcanoes

C. earthquakes

D. new ocean ridges and seafloor

D. New ocean ridges and seafloor: When two plates separate from each other, all the magma inside the Earth rises to the surface and pushes the tectonic plates, creating a new crust in that area. New sea floor is created, having as examples the limit of the so-called Mesoatlantic Ridge, which separates the North American and Euroasian plates in the north of the planet, and in the south, in the Atlantic Ocean, separates the African and South American plates. They are regions where new sea floor is always created.

The features you actually see usually when plates spread is oceanic ridges and new sea floor. But there are exceptions like the Great Rift Valley in East Africa that expose new continental land as they spread. The Ocean ridges would be like the Mid-Atlantic Ridge.