Answer:
c. Compression.
Step-by-step explanation:
Compression is the primary way from which folded mountains are formed. Fold mountains are created where two or more of tectonic plates of earth are pushed together. Due these collision, compressing boundaries and rocks are folded into rocky hills, mountains, and entire mountain ranges. Fold mountains are formed through a process called orogeny which is an event that leads to both structural deformation of the Earth's lithosphere at the margins of convergent plate.