Which of the following processes changes molten rock into an extrusive igneous rock?
a. sedimentation
b. weathering
c. crystallization

Crystallization.

Sedimentation is a process regarding sediment, which is not a part of our scenario, and weathering is to do with the weather, and how it causes breaks down the environment over time.

PS; a question like this would be much better suited as a geography question, rather than computers and technology.