Consider the following features of newer models of motor cars:

Correct Option (B)

The correct answer is B, as features II (Streamlined body) and III (Multipoint fuel injection) primarily contribute to enhanced fuel efficiency in modern motor cars.

• Streamlined Body: A streamlined body design reduces aerodynamic drag, which is the resistance encountered by a vehicle moving through air. Lower drag means the engine requires less power to maintain a given speed, thereby consuming less fuel.
• Multipoint Fuel Injection (MPFI): MPFI systems precisely control the amount of fuel delivered to each cylinder, optimizing the air-fuel mixture for complete combustion. This precision minimizes fuel waste and maximizes energy extraction, leading to improved fuel economy compared to older carbureted or single-point injection systems.

Incorrect Options:

• I. Radial Tyres: While radial tyres offer benefits such as better handling and longer tread life, their primary contribution to fuel efficiency is through reduced rolling resistance compared to bias-ply tyres. However, their impact is generally less significant than that of a streamlined body or advanced fuel injection systems in terms of overall fuel economy improvements. Therefore, including only radial tyres as a primary factor for significant fuel efficiency improvement alongside other options is not the most accurate choice.
• IV. Catalytic Converter with Exhaust: A catalytic converter is an emission control device designed to reduce harmful pollutants in exhaust gases by converting them into less toxic substances. While essential for environmental compliance, catalytic converters can slightly impede exhaust flow, potentially causing a minor reduction in engine efficiency rather than directly improving fuel efficiency. Their primary function is pollution reduction, not fuel economy enhancement.