在平面直角坐标系中，把一条抛物线先向上平移3个单位长度，然后绕原点旋转 $\mathit{180}\mathit{°}$得到抛物线 $\mathit{y}\mathit{=}{\mathit{x}}^{\mathit{2}}\mathit{+}\mathit{5}\mathit{x}\mathit{+}\mathit{6}$，则原抛物线的解析式是 $\mathit{(}$　　 $\mathit{)}$

A． $\mathit{y}\mathit{=}\mathit{-}{\mathit{(}\mathit{x}\mathit{-}\frac{\mathit{5}}{\mathit{2}}\mathit{)}}^{\mathit{2}}\mathit{-}\frac{\mathit{11}}{\mathit{4}}$B． $\mathit{y}\mathit{=}\mathit{-}{\mathit{(}\mathit{x}\mathit{+}\frac{\mathit{5}}{\mathit{2}}\mathit{)}}^{\mathit{2}}\mathit{-}\frac{\mathit{11}}{\mathit{4}}$

C． $\mathit{y}\mathit{=}\mathit{-}{\mathit{(}\mathit{x}\mathit{-}\frac{\mathit{5}}{\mathit{2}}\mathit{)}}^{\mathit{2}}\mathit{-}\frac{\mathit{1}}{\mathit{4}}$D． $\mathit{y}\mathit{=}\mathit{-}{\mathit{(}\mathit{x}\mathit{+}\frac{\mathit{5}}{\mathit{2}}\mathit{)}}^{\mathit{2}}\mathit{+}\frac{\mathit{1}}{\mathit{4}}$