Besides increasing water what should remain consistent while lightening a graded wash?

Correct answer: Brush direction and working pace

The governing concept in a graded wash is a controlled, continuous change in colour value. As more water is added, the brush direction and working pace should remain steady so that adjacent bands join while wet and the transition stays smooth. Changing pigment would alter the colour itself, moving the paper can disturb control, and fully drying every band would create hard steps. Therefore option B is correct.