Which of the following describes the type of rock changes due to direct contact with magma?

The correct answer is contact metamorphism because this term specifically refers to the changes that occur in rocks due to the heat and pressure generated by nearby molten magma. When magma intrudes into existing rocks, the high temperatures can alter the mineral structure and composition of those rocks, resulting in metamorphic rocks that have different physical and chemical properties than the original material. This process typically affects a localized area around the intrusion, leading to the formation of new minerals and textures as the surrounding rock interacts with the heat from the magma.

The other options pertain to different geological processes. Metamorphic changes refer generally to any transformation of rocks under conditions of heat and pressure but do not specify the influence of magma. Hydrothermal changes involve alterations from hot, mineral-rich water rather than direct magma contact. Igneous changes would be more associated with the processes that form igneous rocks directly from the cooling of magma or lava, rather than the metamorphic changes that occur due to the heat from that magma on pre-existing rocks.