Bio ethanol is mixed with ________ to prepare transport fuel

The correct option is petrol.

Bioethanol is an eco-friendly, renewable biofuel produced through the fermentation of sugars found in crops like sugarcane, corn, and wheat.
To make it suitable for use in standard internal combustion engines without requiring major modifications, bioethanol is blended with petrol (also known as gasoline) to create a transport fuel commonly referred to as gasohol or E10, E20, etc. (where the number denotes the percentage of ethanol in the blend).
Blending bioethanol with petrol helps reduce greenhouse gas emissions, improves the octane rating of the fuel for cleaner combustion, and decreases dependence on fossil fuels.