Which is not a primary colour ?

Options

A. Blue
B. Red
C. Yellow
D. White

Answer

To solve the question "Which is not a primary colour?", we need to understand what primary colours are.

### Step-by-Step Solution:

1. **Definition of Primary Colours**:
Primary colours are the basic colours that cannot be created by mixing other colours. In the context of light, the primary colours are red, green, and blue (RGB). In the context of pigments (like paint), the primary colours are red, yellow, and blue (RYB).

2. **Identify the Given Options**:
Typically, the options provided would include colours like red, blue, yellow, green, and white.

3. **Analyze Each Option**:
- **Red**: This is a primary colour (RYB).
- **Blue**: This is also a primary colour (RYB).
- **Yellow**: This is another primary colour (RYB).
- **Green**: This is not a primary colour in the pigment model but is a primary colour in the light model (RGB).
- **White**: This is not a primary colour in either model; it is the combination of all colours in light or the absence of colour in pigments.

4. **Conclusion**:
Based on the analysis, the colour that is not a primary colour is **white**.

### Final Answer:
White is not a primary colour.

---