Rank correlation coefficient is obtained by the formula

A. $${\text{R}} = 1 - 6\frac{{\sum {{\text{D}}^2}}}{{{\text{N}}\left( {{{\text{N}}^2} - 1} \right)}}$$

B. $${\text{R}} = \frac{{1 + 6\sum {{\text{D}}^2}}}{{{{\text{N}}^3} - {\text{N}}}}$$

C. $${\text{R}} = \frac{{1 + 6\sum {{\text{D}}^2}}}{{{{\text{N}}^2} - {\text{N}}}}$$

D. $${\text{R}} = \frac{{1 - 6\sum {{\text{D}}^2}}}{{{{\text{N}}^3} - 1}}$$

Answer: Option A