Final answer:
The amount of octane left after a reaction depends on the conversion efficiency and reaction conditions.
Step-by-step explanation:
The amount of octane left after a reaction depends on the conversion efficiency of the reaction. If the reaction has been completely converted, option a) Complete Conversion, then there will be no octane left. If the conversion is 50%, option b) 50% Conversion, then half of the octane will remain. If the conversion is other than 100% or 50%, the amount of octane left will depend on the reaction conditions, option c) Depends on Reaction Conditions. If the reaction is designed to specifically preserve the octane, then option d) Octane Preservation would be the answer.