If the equation $y=A \cos (Bx-Ct)$ describe the motion of objects ( where $x$ and $y$ are displacements, $t$ is time ), what must be the units of variables $A,B$ and $C$ ?

Question

\[(a)\;m,m^{-1},sec^{-1}\quad (b)\;m^{-1},m,sec\quad (c)\;m^{2},m,sec^{-1}\quad (d)\;m^2,m^{-1},sec^{-1}\]