Step 1: Understanding Primary Colours.
Primary colours are the foundation colours in colour theory. They cannot be created by mixing other colours together. The three primary colours are:
- Red
- Yellow
- Blue
Step 2: Verifying the Options.
- Option (1): 4 primary colours is incorrect, as there are only 3 primary colours in traditional colour theory.
- Option (3): 2 primary colours is incorrect.
- Option (4): 6 primary colours is incorrect.
Conclusion:
Therefore, the correct answer is (2) 3, as there are 3 primary colours in traditional colour theory.