The atlantic ocean is expanding as a result of plate tectonics. which of the following explanations best identifies the type of plate boundary and processes occurring at the mid-atlantic ridge, as shown in the diagram below?

a. a divergent plate boundary exists at the mid-atlantic ridge where plates move away from one another, leading to seafloor spreading.
b. a transform plate boundary exists at the mid-atlantic ridge where two plates slide alongside one another, leading to underwater earthquakes.
c. a convergent plate boundary exists at the mid-atlantic ridge where one plate of oceanic crust is subducted beneath a plate made of continental crust, leading to volcanism.
d. a convergent plate boundary exists at the mid-atlantic ridge where two plates of continental crust meet, leading to the formation of mountain ranges.