(c)
Both produces different ions in solution state
$\left\lbrack Co\left( NH_{3} \right)_{4}Cl_{2} \right\rbrack NO_{2} \rightleftharpoons \left\lbrack Co\left( NH_{3} \right)_{4}Cl_{2} \right\rbrack^{+}NO_{2}^{-}$
$\left\lbrack Co\left( NH_{3} \right)_{4}Cl \bullet NO_{2} \right\rbrack Cl \rightleftharpoons \left\lbrack Co\left( NH_{3} \right)_{4}Cl \bullet NO_{2} \right\rbrack^{+} + Cl^{-}$