Why can a triangle shape be chosen in a warning sign?

Because its angular form can suggest attention and caution

A warning sign must attract attention and suggest that the viewer should be careful. A triangle has a strong angular outline and pointed corners, so it can appear visually sharp, active, or urgent. In many sign systems, a triangle is used as a warning shape, especially when combined with suitable colour and a clear symbol. The shape supports the message but does not communicate every warning by itself.

Option A is correct because the angular form of a triangle can suggest attention and caution. The triangle is not invisible, and it does have corners. It is also not only a flower shape. The exact meaning of a sign depends on its complete design and conventions, but the proposed visual use of the triangle is reasonable and supports the supplied answer.

This is a Class 9 Art Education question. Chapter: Elements of Art. Topic: Shape.