In the coordinate plane, rectangle WXYZ has vertices at (–2, –1), (–2, y), (4, y), and (4, –1). If the area of WXYZ is 18, what is the length of its diagonal?
A.fff\(3\sqrt2\)/fff
B.fff\(3\sqrt3\)/fff
C.fff\(3\sqrt5\)/fff
D.fff\(3\sqrt6\)/fff
E.fff\(3\sqrt7\)/fff
