Two voltameters one of copper and other of silver, are joined in parallel. When a total charge $q$ flows through a voltameters, equal amount of metals are deposited. If the electrochemical equivalents of copper and silver are $z_1\: and \: z_2$ respectively the charge which flows through the silver voltameter is

Question

$\begin {array} {1 1} (A)\;\large\frac{q}{1+\large\frac{z_1}{z_2}} & \quad (B)\;\large\frac{q}{1+\large\frac{z_2}{z_1}} \\ (C)\;q\large\frac{z_1}{z_2} & \quad (D)\;q\large\frac{z_2}{z_1} \end {array}$