which statement best describes how a ridge forms?
a two tectonic plates move away from each other, causing lava to spew out of the ground and harden
b two tectonic plates move away from each other, causing them to push up against each other
c two tectonic plates move towards each other, causing one plate to slip under the other
d two tectonic plates move towards each other, causing a sudden drop in the ocean floor that can be miles deep