$(9)$ The correct calculation for determine the displacement at Point C of the following beam by using the graph$-$multiplication method is $().$

A$.={\displaystyle \underset{?}{\overset{?}{}}}{\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}\frac{1}{EI}\frac{M_P}{b}ar(M)dx=\frac{1}{EI}(\frac{1}{2}\frac{1}{2}l\frac{1}{2}l)\frac{5Pl}{6}$

B$.={\displaystyle \underset{?}{\overset{?}{}}}{\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}\frac{1}{EI}\frac{M_P}{b}ar(M)dx=\frac{1}{EI}(\frac{1}{2}lPl)(\frac{1}{6}\frac{l}{2})$

C$.={\displaystyle \underset{?}{\overset{?}{}}}{\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}\frac{1}{EI}\frac{M_P}{b}ar(M)dx=\frac{1}{EI}(\frac{1}{2}lPl)\frac{1}{6}l$