Choose the correct one

A. $${\text{MR}} = {\text{AR}}\left( {\frac{{\text{e}}}{{{\text{e}} + 1}}} \right)$$

B. $${\text{AR}} = {\text{MR}}\left( {\frac{{\text{e}}}{{{\text{e}} + 1}}} \right)$$

C. $${\text{MR}} = {\text{AR}}\left( {\frac{{{\text{e}} - 1}}{{\text{e}}}} \right)$$

D. $${\text{AR}} = {\text{MR}}\left( {\frac{{{\text{e}} + 1}}{{\text{e}}}} \right)$$

Answer: Option C