Geology, Please help me!!?

(Q001) The following questions will give you a sense of the rates at which uplift and erosion take place. We will assume that uplift and erosion do not occur at the same time—that mountains are first uplifted, and only then does erosion begin—whereas the two processes actually operate simultaneously.

Part 1.a. If mountains rose by 1 mm/yr, how high would they be (in meters) after 1,000 years? 10 million years? 50 million years?

 a. 1,000 yr: 1 m; 10 million yr: 10,000 m; 50 million yr: 50,000 m

 b. 1,000 yr: 10 m; 10 million yr: 100,000 m; 50 million yr: 500,000 m

 c. 1,000 yr: 1,000 m; 10 million yr: 10 million m; 50 million yr: 50 million m

 d. 1,000 yr: 100 m; 10 million yr: 1 million m; 50 million yr: 5 million m