Efficiency of a screw jack is given by

• A. <img src="/_files/images/mechanical-engineering/theory-of-machines/485-170-1.png">
• B. <img src="/_files/images/mechanical-engineering/theory-of-machines/485-170-2.png">
• C. <img src="/_files/images/mechanical-engineering/theory-of-machines/485-170-3.png">
• D. <img src="/_files/images/mechanical-engineering/theory-of-machines/485-170-4.png">