(c)
Cuprammonium salt, $\left\lbrack Cu\left( NH_{3} \right)_{4} \right\rbrack SO_{4}$
$\left\lbrack Cu\left( NH_{3} \right)_{4} \right\rbrack SO_{4} \rightleftharpoons \left\lbrack Cu\left( NH_{3} \right)_{4} \right\rbrack^{2 +} + SO_{4}^{2 -}$
So, it will give two ions in water