Answer:
Option (D)
Explanation:
The two plates move in the opposite direction in a divergent type of plate motion as a result of which seafloor spreading takes place where the magma is forced to come out to the surface of the ocean floor. This allows the addition of new materials to the crust, thereby forming the mid-oceanic ridge. This type of plate boundary leads to the formation of volcanoes and deep-focus earthquakes are often generated.
Thus, the mid-oceanic ridge is formed when magma pushes upward and adds new materials to the crust.
Hence, the correct answer is option (D).
