Question

Plz solve Qno 12 th and also explain why 1 st option is incorrect?

Answer 1

The first option is incorrect because when the double bond will break the positive charge will go in dir of more CH3 as they show +I effect
+ve charge will go there by 1-2 methyl shift of 2 quaternary carbon towards secondary carbon.
Now as there is +ve charge on 2 carbon from left OH group will attack there making C option the major product and A option wrong.