Poster colours are especially suitable for which type of shapes?

Correct answer: Clear and flat shapes

The governing concept is the visual quality of opaque poster colour. It produces strong, relatively even areas of colour and can define clear boundaries, so it is especially effective for bold, flat shapes in illustrations, designs and posters. A light preliminary sketch helps the artist keep those boundaries neat. Option A is correct. Invisible shapes, sculptures and thread forms are not the ordinary two-dimensional uses described by this medium.