Alcohols, Phenols and Ethers Part 1

(1) In compound A, positive charge on O atom is not stable that is why ‌

⊕

O

H2 get's removed.
(2) In Carbocation (B), two α−H present and after 1, 2-methyl shift number of α−H becomes six so it becomes more stable as far carbocation when number of α-H increases stability increases.
(3) Among product D, E and F, D is major product as in case of alkene most stable, alkene are those which have more α−H. And every reactant produce that product which is more stable.