Question 27In the figure, $AB\perp BC,$ $BC\perp CD,$ and $BC$ is tangent to the circle with center $O$ and diameter $AD.$ In which one of the following cases is the area of $ABCD$ an integer? $AB=3,$ $CD=1$$AB=5,$ $CD=2$$AB=7,$ $CD=3$$AB=9,$ $CD=4$$AB=11,$ $CD=5$
