Consider following carbocations

If most stable carbocation = x; Least stable carbocation = y
(Here x & y are numbers of above carbocations) then value of x + y is_____

x = 3 / y =5.

Hyperconjugation effect decides the stability of free radicals, carbocations and alkenes, Hyperconjugation effect depends on the number of alpha hydrogen present on the alpha carbon with reference to the benzene ring or the radical/C=C/positive or the carbon chain. More the hydrogens more the hyperconjugation forms. In option 3 we can see 3 hyperconjugation forms.