c$.$ Phenylalanine $C$ can be synthesised from $3-$phenylpropanoic acid A through intermediate $B$ using the well$-$known Hell$-$Vollhard$-$Zelinsky reaction shown in Figure $2.$

$($i$)$ Identify the structure of the desired intermediate $B.$

$[2$ marks$]$

$($ii$)$ Draw the mechanism for the formation of intermediate $B$ from $3-$phenylpropanoic acid $A.$

$[6$ marks$]$

$($iii$)$ Draw the mechanism for the formation of phenylalanine $C$ from intermediate $B.$

$[4$ marks$]$

$($iv$)$ Outline two drawbacks to this method of amino acid synthesis.

$[2$ marks$]$

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