Which of the following statements are true?
I. In the luminous zone of candle flame, vaporised wax gets oxidised to carbon dioxide which burns with a blue flame.
II. There is no burning in the dark inner zone of the flame.
III. Non luminous zone is the hottest part of the flame.
IV. Luminous zone of a flame is mainly due to incomplete burning of carbon.

Options

A. I and III only
B. II and III only
C. II, III and IV only
D. All of these

Explanation

To determine which statements are true regarding the zones of a candle flame, let's analyze each statement step by step.

### Step 1: Analyze Statement I
**Statement I:** In the luminous zone of a candle flame, vaporized wax gets oxidized to carbon dioxide which burns with a blue flame.

- The luminous zone of a candle flame is characterized by a yellow flame, not a blue flame. The yellow color is due to the incomplete combustion of carbon particles that are produced when the wax vapor burns. Therefore, this statement is **false**.

### Step 2: Analyze Statement II
**Statement II:** There is no burning in the dark inner zone of the flame.

- The dark inner zone, also known as the inner core, lacks sufficient oxygen for combustion to occur. Since combustion requires oxygen, and there is none in this zone, this statement is **true**.

### Step 3: Analyze Statement III
**Statement III:** Non-luminous zone is the hottest part of the flame.

- The non-luminous zone, or outer zone, has a complete combustion process due to an excess supply of oxygen. This zone is indeed the hottest part of the flame and burns with a blue color. Therefore, this statement is **true**.

### Step 4: Analyze Statement IV
**Statement IV:** Luminous zone of a flame is mainly due to incomplete burning of carbon.

- The luminous zone is characterized by incomplete combustion, which results in the production of carbon particles that glow yellow. This is due to the limited supply of oxygen. Therefore, this statement is **true**.

### Conclusion
After analyzing all the statements, we find:
- Statement I: False
- Statement II: True
- Statement III: True
- Statement IV: True

Thus, the true statements are II, III, and IV.

### Final Answer
The correct statements are II, III, and IV.

---