Hyperconjugation describes the orbital interactions between the p-systems and the adjacent s-bond of the substituent group(s) in organic compounds. Hyperconjugation is also called as Baker and Nathen effect. The necessary and sufficient condition for the hyperconjugation are : i) Compound should have at least on sp2 hybrid carbon of either alkene, carbocation or alkyl free radical. ii) A-carbon with respect to sp2 hybrid carbon should have at least one hydrogen. Hyperconjugation are of three types: (i) s(C-H), p-conjugation. (iii) s(C-H), positive charge conjugation iv) s(C-H), odd electron conjugation The hyperconjugation may be represented as Number of resonating structures due to hyperconjugation = (n + 1) where n is the number of a-hydrogen. Greateris the number of such forms, more is the stability of the species under considersation. Hyperconjugation is possible in which of the following species ?