The most hottest part of flame is

Options

A. blue zone
B. Innermost zone
C. middle zone
D. None of these

Explanation

To determine the hottest part of a flame, we need to analyze the different zones of a flame and their characteristics.

### Step-by-Step Solution:

1. **Understanding Flame Structure**: A flame consists of different zones, each with varying temperatures and characteristics. The main zones are:
- Luminous zone (outer zone)
- Non-luminous zone (inner zone)
- Intermediate zone (middle zone)

2. **Identifying the Non-Luminous Zone**: The non-luminous zone is where complete combustion occurs. This zone is characterized by a blue color and is typically the hottest part of the flame. This is because it has a sufficient supply of oxygen, which allows for the complete burning of the fuel.

3. **Complete Combustion**: In the non-luminous zone, the presence of ample air (oxygen) leads to complete combustion. This results in higher temperatures compared to other zones where incomplete combustion may occur, leading to the production of soot and a yellow flame.

4. **Conclusion**: Based on the characteristics of the flame zones, the hottest part of the flame is the non-luminous zone, which is also referred to as the blue zone.

5. **Final Answer**: Therefore, the correct option is **A) blue zone**.