The efficiency of a hydraulic press is given by (where W = Weight lifted by ram, P = Force applied on plunger, A = Area of ram, and a = Area of plunger)

• A. <img src="/_files/images/mechanical-engineering/hydraulic-machines/205-164-1.png">
• B. <img src="/_files/images/mechanical-engineering/hydraulic-machines/205-164-2.png">
• C. <img src="/_files/images/mechanical-engineering/hydraulic-machines/205-164-3.png">
• D. <img src="/_files/images/mechanical-engineering/hydraulic-machines/205-164-4.png">