Question

where two continental plates collide,
a. there will likely be no earthquakes until plate motion stops.
b. the crust will likely become very thin over millions of years.
c. a mountain range will likely build up over millions of years.
d. all of these

Explanation:

When two continental plates collide, neither subducts (both are low-density), so crust crumples and uplifts to form mountain ranges over millions of years. Earthquakes occur during collision (A is wrong); crust thickens, not thins (B is wrong). Thus D is incorrect.

Answer:

C. a mountain range will likely build up over millions of years.