Can a quadrilateral ABCD be a parallelogram if ∠D + ∠B = 180°?

Dear Student

Yes, a quadrilateral ABCD be a parallelogram if ∠D + ∠B = 180° but it shouldalso fulfilled some conditions which are:
(a) The sum of the adjacent angles should be 180°.
(b) Opposite angles must be equal.

Thanks