The species shown below represents _____ of the reaction between isopropyl alcohol and hyd...

The species shown below represents _____ of the reaction between isopropyl alcohol and hydrogen bromide.

A) the alkyloxonium ion intermediate

B) the transition step of the bimolecular proton transfer

C) the transition state of the attack of the nucleophile on the carbocation

D) the transition state of the unimolecular dissociation