What is denatured spirit? 

Ethanol and methanol (5%)

The correct answer is option 3. Ethanol and methanol (5%).

Ethanol is an important industrial solvent. To prevent the misuse of ethanol produced for industrial use, it is made unfit for drinking by adding poisonous substances like methanol to it. Dyes are also added to colour the alcohol blue so that it can be identified easily. This is called denatured alcohol.