First notice that the figure’s not drawn the scale. Remember
that when this happens you cannot trust a drawing. Look for information
we are given. The only information we are given is that the line
segments AD and DC are equivalent. Point B, wherever it may be, would
be the same perpendicular distance from a AD as from DC. Therefore
we have two triangles: ADB and BDC with the same base and the same height.
Remember that any side of a triangle can serve as the base as long as you
know the perpendicular distance to the opposite angle. Therefore
the areas of these two triangle's art equal. C is the correct answer.