Identify the initiation step$(s)$ $(X)$ and termination step$(s)$ $(Y)$ of free radical chlorination of $CH_4$ from the following:
$a) \dot{C}H_3 + \dot{Cl} \rightarrow CH_3-Cl$
$b) \dot{Cl} + \dot{Cl} \rightarrow Cl_2$
$c) \dot{C}H_3 + Cl_2 \rightarrow CH_3-Cl + \dot{Cl}$
$d) Cl_2 \rightarrow 2\dot{Cl}$
$e) CH_4 + \dot{Cl} \rightarrow \dot{C}H_3 + HCl$
$f) \dot{C}H_3 + \dot{C}H_3 \rightarrow CH_3-CH_3$

• A
  $X: c, d; Y: a, b$
• B
  $X: b, d; Y: a, c, e$
• C
  $X: d, e; Y: b, c, f$
• D
  $X: d; Y: a, b, f$