The correct answer is C. Octane number.
Octane number is a measure of a fuel’s ability to resist knocking or pinging in an engine. Knocking occurs when the air-fuel mixture in the engine ignites before the spark plug fires. This can cause the engine to lose power and efficiency, and can also damage the engine.
The octane number of a fuel is determined by its resistance to knocking. A higher octane number indicates a fuel that is more resistant to knocking. Fuels with higher octane numbers are typically used in high-performance engines, which are more likely to experience knocking.
The octane number of a fuel is determined by a variety of factors, including the type of hydrocarbons in the fuel, the compression ratio of the engine, and the temperature of the engine.
The octane number of a fuel can be increased by adding octane boosters to the fuel. Octane boosters are typically made from hydrocarbons that have a high octane number.
The octane number of a fuel is an important factor in determining the performance and efficiency of an engine. A fuel with a high octane number will help to prevent knocking and will allow the engine to operate at its maximum potential.
The other options are incorrect because:
- Cetane number is a measure of a diesel fuel’s ignition quality.
- Gold number is a measure of the dispersibility of a pigment in a liquid.
- Added unlead compounds are additives that are added to gasoline to reduce emissions and improve performance.