Three identical square sheets of paper each with side length 6 are stacked on top of each other. The middle sheet is rotated clockwise 30^{\circ} about its center and the top sheet is rotated clockwise 60^{\circ} about its center, resulting in the 24 -sided polygon shown in the figure below. The area of this polygon can be expressed in the form a-b \sqrt{c}, where a, b, and c are positive integers, and c is not divisible by the square of any prime. What is a+b+c ?

**Answer Choices**

A. 75

B. 93

C. 96

D. 129

E. 147