A hydrocarbon 'P' $(C_4H_8)$ on reaction with HCl gives an optically active compound 'Q' $(C_4H_9Cl)$ which on reaction with one mole of ammonia gives compound 'R' $(C_4H_{11}N)$. 'R' on diazotization followed by hydrolysis gives 'S'. Identify P, Q, R and S.

A

B

C

D