The following relationship among the correlation coefficients (r) and the two regression coefficients b_yx and b_xy exists.

A. $${{\text{r}}^2} = {{\text{b}}_{{\text{xy}}}} \cdot {{\text{b}}_{{\text{yx}}}}$$

B. $${\text{r}} = \sqrt {{{\text{b}}_{{\text{xy}}}} \cdot {{\text{b}}_{{\text{xy}}}}} $$

C. $${{\text{r}}^2} = \frac{{{{\text{b}}_{{\text{yx}}}}}}{{{{\text{b}}_{{\text{xy}}}}}}$$

D. $${\text{r}} = \sqrt {\frac{{{{\text{b}}_{{\text{yx}}}}}}{{{{\text{b}}_{{\text{xy}}}}}}} $$

Answer: Option A