The correct answer is: C. There is no reaction.
Glycerol is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. It is a trihydric alcohol, meaning that it has three hydroxyl groups (-OH). Potassium permanganate (KMnO4) is a dark purple solid that is used as a strong oxidizing agent.
When a drop of glycerol is added to crushed KMnO4 spread on a paper, there is no reaction. The glycerol does not react with the potassium permanganate. This is because the hydroxyl groups in the glycerol are not strong enough to oxidize the potassium permanganate.
The other options are incorrect because they describe reactions that do not occur. Option A is incorrect because there is no crackling sound. Option B is incorrect because there is no violent explosion. Option D is incorrect because the paper does not ignite.