Haloalkanes and Haloarenes Part 1

2 - methylbut - 1, 3 - diene 1 - bromo 3 - methylbut - 2 - ene
This addition is known as 1, 4 - addition.
Mechanism This reaction can undergoes two pathways Path A Out of the two intermediates formed in two paths, the path B intermediate is more stable as it has more stable carbocation. So, major product will be formed because of path B. 1, 2 -addition product is formed at low temperature and will be less stable as double bond is less substituted. 1, 4 - addition is thermodynamically stable product as double bond is more substituted. As diene is in excess and HBr is limited in reaction, so diene cannot be formed.
So option (b) is incorrect.