Units A, B, and C Are Sedimentary Rocks; Unit a Is

Units A, B, and C are sedimentary rocks; unit A is the oldest and unit C is the youngest. The sedimentary rocks are cut by a fault, indicated by the bold line. The fault dips 60° to the northwest as shown by the strike and dip symbol.

-Why is unit A wider north of the fault than it is south of the fault?

A) Deeper levels of the structure are exposed on the north side of the fault.
B) Erosion has removed most of unit A south of the fault.
C) Faulting has thinned unit A south of the fault.
D) Unit A had a variable thickness prior to faulting.