b
The two possible isomers for the given octahedral complex are \([M(NH_3)_5SO_4]Cl\) and \((M(NH_3)_5Cl]SO_4\). They respectively give chloride ion (indicated by precipitation with \(BaCl_2\) ) and \(SO_4\) ion (indicated by precipitation with \(AgNO_3\)). Hence the type of isomerism exhibited by the complex is ionization isomerism