Question: Product (P) is:
The addition of HBr in the presence of peroxide takes place through the free radical addition mechanism. The product that is formed during the free radical addition mechanism is usually the anti-Markovnikov product. When HBr is added to unsymmetrical alkenes in the presence of peroxide, the Br is attached to that double-bonded carbon which contains more hydrogen atoms thereby forming an anti-Markovnikov addition product. This reaction is also known as the Kharash effect or peroxide effect.
Hence, the correct answer is option (b).