The correct option is B 2c2ab
ax±by±c=0⇒x±c/a+y±c/b=1
which meets on axes at A(ca,0),C(−ca,0),B(0,cb) and D(0,−cb)
Therefore, the diagonals AC and BD of quadrilateral ABCD are perpendicular, hence it is a rhombus whose area is given by =12AC×BD=12×2ca×2cb=2c2ab.