The hyperconjugative stabilities of tert-butyl cation and `2`-butene, respectively, are due to

Options

A. `sigma to pi " and " sigma to pi^(**)`
B. `sigma to ` vacant p and `pi to pi^(**)`
C. `sigma to sigma^(**)` and `sigma to pi`
D. `sigma to ` vacant p and `sigma to pi^(**)`

Answer

D

Explanation

tert-Butyl cation is more stable than isopropylcation because of better hyperconjuction ( `sigma`- vacant p orbital overlap ), Whereas trans-2-butene is more stable than propane because of `sigma-pi^(**)` orbital overlap.