A triangle is partitioned into three triangles and a quadrilateral by drawing two lines from vertices to their opposite sides. The areas of the three triangles are 3,7 , and 7 , as shown. What is the area of the shaded quadrilateral?
Answer Choices
A. 15
B. 17
C. \dfrac{35}{2}
D. 18
E. \dfrac{55}{3}