Arrange the following compounds in order of decreasing reacivity towards EAS reactions.

Explanation

(a) `IIgtIgtVgtIIIgtIV`
(b) `IgtIIgtIIIgtIV` [This is due to hyperconjugation (H.C.). I has three H.C. structures, II has two H.C. structures, III has one H.C. structure and IV has no H.C. structure.]