This establishes that the highest mountain ranges often cause extreme erosive forces. This helps explain why the highest ranges are found in the places where erosive forces are most prevalent: the height helps to create those forces.

If anything, this makes the conflict harder to reconcile. If (B) were true, we'd expect the highest mountain ranges to be even more vulnerable to erosive forces than shorter mountain ranges. So, why would the highest mountain ranges be found where the erosive forces are the greatest?

How some lower mountain ranges are formed doesn't relate to the highest mountain ranges. This doesn’t explain why the highest mountain ranges are found where erosive forces are most prevalent.

Even if precipitation can differ over the lifetime of a mountain range, we still know that the highest mountain ranges tend to be found in places where erosive forces (such as precipitation) are most prevalent. (D) doesn't provide a theory about why this could be the case. If you think (D) suggests the erosive forces in these areas might be low, that contradicts the facts. The highest mountain ranges are found in places where erosive forces are most prevalent, even if there are variations in those forces over time.

Even if this is true, we still don't have any theory about why the highest mountain ranges are found in areas with the most prevalent erosive forces. It's not clear how sinking crusts relate to erosive forces.