Need explanation. Ans C
I'm not very sure that this is the mechanism but it looks feasible and there's no other way I found you could get any of the other options as product.
Why is C dominant over A and B
A can be formed if O- directly attacks the carbocation
B when the alkene resonates with the carbocation and then O- attacks
An oxygen is missing in A and a carbon is missing in B.
Ah right overlooked that