Q$4.$ Link $5$ in problem $2\mathrm{.}33$ in Ghosh$-$Mallik contains of two mutually perpendicular slots in which links $3$ and $4$ slide. Link $5$ is hinged to the fixed link at $O$ and link $2$ is hinged to the fixed link at $C.$ Link $2$ is also hinged to sliders $3$ and $4$ at A and $B,$ respectively. It is further given that $OB=AB=BC.$ Obtain all the relative instantaneous centres and determine $\frac{{}_2}{{}_5}.$