Correct answer is (a) SAR=\(\frac{\eta}{C}\frac{L}{D}\frac{1}{W}\)
The best explanation: The correct formula for specific air range is given by SAR=\(\frac{\eta}{C}\frac{L}{D}\frac{1}{W}\) where η is propeller efficiency, C is specific fuel consumption, L is lift, D is drag, W is weight. SAR can also be written as SAR=\(\frac{V}{CP}\) where v is velocity, C is specific fuel consumption and P is power.