Let R be a square region and n \geq 4 an integer. A point X in the interior of R is called n-ray partitional if there are n rays emanating from X that divide R into n triangles of equal area. How many points are 100-ray partitional but not 60-ray partitional?
Answer Choices
A. 1500
B. 1560
C. 2320
D. 2480
E. 2500