The open “Sigrees” or coal stoves often require fanning to sustain burning because of A. Tendency of carbon dioxide to form a layer along with dust smoke B. Lack of oxygen in the surroundings of sigrees C. Accumulation of smoke and dust over the sigrees D. Interrupted release of moisture from the material

The correct answer is: B. Lack of oxygen in the surroundings of sigrees.

Open “Sigrees” or coal stoves often require fanning to sustain burning because of the lack of oxygen in the surroundings of the sigrees. When a coal stove is burning, it consumes oxygen from the air. If there is not enough oxygen in the air, the fire will start to die down. Fanning

The other options are incorrect because:

• Option A is incorrect because carbon dioxide is a product of combustion, not a cause of it.
• Option C is incorrect because smoke and dust are not the main reason why sigrees require fanning.
• Option D is incorrect because the release of moisture from the material does not affect the amount of oxygen in the air.