Consider the following sequence of reactions.


The correct reagents $(\mathbf{P}, Q, R$ and $\mathbf{S})$ required are:

• Correct answer
  A

  $\mathbf{P}=\mathrm{Br}_2 /$ red phosphorous; $\mathbf{Q}=\mathrm{H}_2 \mathrm{O} ; \mathbf{R}=\mathrm{SOCl}_2 ; \mathbf{S}=\mathrm{H}_2, \mathrm{Pd}_2-\mathrm{BaSO}_4$
• B

  $\mathbf{P}=\mathrm{Br}_2 /$ red phosphorous; $\mathbf{Q}=\mathrm{H}_3 \mathrm{O}^{+} ; \mathbf{R}=\mathrm{SOCl}_2 ; \mathbf{S}=\mathrm{LiAlH}_4$
• C

  $\mathbf{P}=\mathrm{Br}_2 / \mathrm{NaOH} ; \mathbf{Q}=\mathrm{H}_2 \mathrm{O} ; \mathbf{R}=\mathrm{PCl}_3 ; \mathbf{S}=\mathrm{DIBAL}-\mathrm{H}$
• D

  $\mathbf{P}=\mathrm{PBr}_3 ; \mathbf{Q}=\mathrm{H}_3 \mathrm{O}^{+} ; \mathbf{R}=\mathrm{Cl}_2 / \mathrm{FeCl}_3 ; \mathbf{S}=\mathrm{Pd}-\mathrm{BaSO}_4$

Hence, the correct answer is option: 'A'.