(CH3)3C+−Tertiary carbocation(CH3)2C+H−Secondary carbocationCH3−C+H2−Primary carbocationC+H3−Methyl carbocation
Stability of carbocations depends upon the electron releasing groups. The given carbocations stability can be explained by hyperconjugation effect. More the number of alpha hydrogen, more are number of hyperconjugation structures, hence, more is the stability of carbocation.
Thus, the observed order of stability for carbocations is as follows: tertiary > secondary > primary > methyl
Hence, option C is correct.