Step 1: Understanding the Number of Main Colours.
In colour theory, there are three main colours, also known as primary colours: red, blue, and yellow. These three colours are the basis for all other colours, as other colours can be created by mixing different combinations of these primary colours.
Step 2: Verifying the Options.
- Option (1): There are three main colours, red, blue, and yellow, making this the correct answer.
- Option (2): Seven colours is incorrect; it refers to the colours of the rainbow, but not the main colours.
- Option (3): Two main colours is incorrect.
- Option (4): Five main colours is incorrect.
Conclusion:
Therefore, the correct answer is (1) Three.