Passage-III : The binary compounds of oxygen with other elements are called oxides. They are classified either depending upon their acid - base characteristics or on the basis of oxygen content. a ) Normal oxides : These oxides which contain oxygen atoms as permitted by the normal oxidation number, i.e., -2. Normal oxide may be acidic, basic, amphotericor neutral.b) Polyoxides : The oxides which contain oxygen atoms different than those permitted by the normal oxidation number of -2. i) Peroxides : Two oxygen atoms are linked to each other and oxygenhas -I oxidation number. They contain (O-O)^(2) unit. ii) Superoxides : These oxides contain (O-O)^(-1) units, i.e., each O-atom has oxidation number -1//2. c ) Suboxides : These contain low content of oxygen than expected. d) Mixed oxides : These oxides are made of two simpler oxides.Which of the following pairs contains mixed oxides?