Equilateral \triangle A B C has side length 2, M is the midpoint of \overline{A C}, and C is the midpoint of \overline{B D}. What is the area of \triangle C D M ?
Answer Choices
A. \dfrac{\sqrt{2}}{2}
B. \dfrac{3}{4}
C. \dfrac{\sqrt{3}}{2}
D. 1
E. \sqrt{2}