Choose the odd one out from each of the following sets:
(I)p→Hadean,q→Phanerozoic,r→Palaeozoic,s→Proterozoic
(II)p→Ordovician,q→Permian,r→Silurian,s→Cretaceous
(III)p→Oligocene,q→Miocene,r→Pliocene,s→Permian
(IV)p→Cenozoic,q→Palaeozoic,r→Jurassic,s→Mesozoic