Judge the Following Sentence According to the Criteria Given Below

Multiple Choice

Judge the following sentence according to the criteria given below. Mountains continue to rise long after tectonic forces cease to thicken crust and drive uplift along faults because mountains result both from tectonic deformation and isostatic response to erosion.

A) The assertion and the reason are both correct, and the reason is valid.
B) The assertion and the reason are both correct, but the reason is invalid.
C) The assertion is correct but the reason is incorrect.
D) The assertion is incorrect but the reason is correct.
E) Both the assertion and the reason are incorrect.