The correct answer is B) Turbocharged. A turbocharged engine has the lowest specific fuel consumption compared to the other options. This is because a turbocharger uses the exhaust gases to drive a turbine, which then compresses the intake air. This increased air density allows the engine to produce more power from the same amount of fuel, resulting in improved fuel efficiency and lower specific fuel consumption. The other options are less efficient: A) Natural aspiration does not provide any boost to the intake air, C) Roots blower and D) Piston blower use mechanical means to compress the intake air, which requires additional power from the engine, reducing overall efficiency.