The Equation for the Standardized Regression Equation Is ______ $r^{2}=\frac{b_{1} S P_{X_{1} Y}+b_{2} S P_{X_{2} Y}}{S S_{Y}}$

The equation for the standardized regression equation is ______.

A) b₁X₁ + b₂X₂ + a
B) $r^{2}=\frac{b_{1} S P_{X_{1} Y}+b_{2} S P_{X_{2} Y}}{S S_{Y}}$
C) $a=M_{Y}-b_{1} M_{X_{1}}-b_{1} M_{X_{2}}$
D) $\widehat{Z_{Y}}=\beta_{1}\left(z_{X_{1}}\right) +\beta_{2}\left(z_{X_{2}}\right)$