A frame is subjected to a load $P$ as shown in the figure. The frame has a constant flexural rigidity $EI$. The effect of axial load is neglected. The deflection at point $A$ due to the applied load $P$ is

1. $\dfrac{1}{3}\dfrac{PL^3}{EI} \\$
2. $\dfrac{2}{3}\dfrac{PL^3}{EI} \\$
3. $\dfrac{PL^3}{EI} \\$
4. $\dfrac{4}{3}\dfrac{PL^3}{EI}$