Step 1: Understanding Cool Colours.
Cool colours are those that are often associated with calmness, water, and the sky. These colours typically include blue, green, and purple. Cool colours evoke a sense of serenity and peace.
Step 2: Evaluating the Options.
- Option (1): Red is a warm colour, associated with energy and warmth.
- Option (2): Orange is a warm colour, evoking feelings of energy and heat.
- Option (3): Yellow is a warm colour, representing sunshine and warmth.
- Option (4): Green is a cool colour, often associated with nature, grass, and calmness.
Conclusion:
Therefore, the correct answer is (4) Green, as it is a cool colour.