Which of the following is the most stable carbocation? (CPMT 2010) (a) C H CH (b) CH C

There are the three main factors which increase the stability of carbo cations- 1. +I effect 2. +M effect 3. Hyperconjugation effect In case of benzyl carbocation, +M effect makes it more stable then primary, secondary or tertiary carbocation. But in tertiary butyl carbocation 9-hydrogen atoms contribute towards hyperconjugation, which makes it even more stable than benzyl carbocation.