What can be done to create a thin layer of acrylic colour?

Correct answer: Add a limited amount of water

To create a thin acrylic layer, a small or controlled amount of water can be mixed into the paint, making it less viscous and easier to spread. Therefore, option B is correct. Water should be used carefully because excessive dilution can weaken the paint film and reduce adhesion, especially on an unsuitable surface. Sand adds texture, drying the brush does not thin paint, and cutting paper is unrelated. The required amount depends on the desired transparency and flow.