Intermediate(s) involved in the following reaction is(are)

Concept:

A 3,3-sigmatropic rearrangement, often referred to as a [3,3]-sigmatropic rearrangement, is a type of pericyclic reaction. In this rearrangement, a sigma (σ) bond between two carbon atoms shifts, resulting in the migration of substituents and the formation of a new sigma bond.

There are two common types of [3,3]-sigmatropic rearrangements:

• Cope Rearrangement: In a Cope rearrangement, a 1,5-diene (a compound with two alternating double bonds separated by four carbon atoms) undergoes a [3,3]-sigmatropic rearrangement to form a different diene. The transition state of a Cope rearrangement involves a six-membered ring.
• Claisen Rearrangement: In a Claisen rearrangement, an allyl vinyl ether (a compound with a double bond adjacent to an oxygen atom) undergoes a [3,3]-sigmatropic rearrangement to form a different allyl vinyl ether. The transition state of a Claisen rearrangement involves a five-membered ring.

Explanation:

The above reaction undergoes 3,3-sigmatropic rearrangement where bond always breaks from C-1 position followed by electrophilic reaction. 

Conclusion:

The intermediate involved in the reaction is Intermediate(I) i.e. only B.