The maximum efficiency of screw jack is

• A. \(\frac{1-sin~\phi}{1+sin~\phi}\)
• B. \(\frac{1+sin~\phi}{1-sin~\phi}\)
• C. \(\frac{{1 - tan\phi }}{{1 + tan\phi }}\)
• D. \(\frac{{1 + tan\phi }}{{1 - tan\phi }}\)