The polygon is formed by a triangle and a rectangle:
Area of a rectangle = lenght x width
A1 = (4 x 3)
Area of a triangle = 1/2 x base length x heigth
A2 = 1/2 (9x4)
Add both areas
Area of the polygon = A1+ A2 = (4 x 3 ) + 1/2 (9 x 4)
answer : option A