Read or check out the video on metamorphic how does contact metamorphism of pre-existing sedimentary or igneous rocks occur? select one:

a) by hot water circulating through oceanic crust.
b) by high pressure conditions in a subduction zone.
c) by heat from nearby magma called an igneous intrusion.
d) by high temperatures and high pressures during burial.

Metamorphism of pre-existing sedimentary or igneous rocks occurs by heat from nearby magma called an igneous intrusion.

Option C

Explanation:

Contact metamorphism occurs when the hot igneous rock thrusts into some some other rock which exists previously. Then the pre-existing rock is baked by heat and during this process no additional pressure is added and this leads to the change in the mineral structure of the rock. Contact metamorphism is occurred only with heat and not by adding any additional pressure on the rock.