What is the area of this triangle?
A. A=1/2(y3-y2)(x3-x1)
B. A=1/2(y3-y1)(x3-x1)
C. A=1/2(y3-y1)(x3-x1)
D. A=1/2(y2-y1)(x3-x1)
E. A=1/2(y2-y1)(x2-x1)
