Step 1: Colour Psychology Basics
In psychology and visual arts, colours are associated with different emotions. These associations are based on cultural as well as psychological interpretations.
Step 2: Emotional Interpretation of Orange
Orange is a warm, vibrant colour often associated with:
- Joy
- Energy
- Enthusiasm
- Warmth
- Happiness
It combines the energy of red and the cheerfulness of yellow. Thus, orange tends to represent uplifting and cheerful feelings.
Step 3: Eliminating Wrong Choices
- (A) Knowledge: Often linked with blue
- (B) Sadness: Usually associated with blue or grey
- (D) Anger: Represented by red
Therefore, the correct and most psychologically accepted association for orange is happiness.
\[
\boxed{\text{Happiness}}
\]