The Main Difference Between a Primary Coast and a Secondary

The main difference between a primary coast and a secondary coast is:

A) primary coasts represent the main coastline, while secondary coasts are the shoreline within coastal inlets.
B) primary coasts are shaped principally by nonmarine processes, while secondary coasts are shaped primarily by marine processes.
C) primary coasts are relatively even, smooth coastlines, while secondary coasts are characterized by numerous headlands and inlets.
D) primary coasts are much longer than secondary coasts.