The Mississippi River Cuts Through Silurian-Aged Dolomite Between Northwestern Illinois

The Mississippi River cuts through Silurian-aged dolomite between northwestern Illinois and eastern Iowa.Which is older? How do you know?

A) Dolomite;the principle of superposition
B) Mississippi; the principle of original horizontality
C) Dolomite; the principle of cross-cutting relationships
D) Mississippi; the principle of lateral continuity