Identify the initiation step \(/ \mathrm{s}(\mathrm{X})\) and termination \(\mathrm{step} / \mathrm{s}(\mathrm{Y})\) of free radical chlorination of \(\mathrm{CH}_4\) from the following.
a) \(\dot{\mathrm{C}}_3+\dot{\mathrm{C}} \mathrm{l} \rightarrow \mathrm{CH}_3-\mathrm{Cl}\)
b) \(\dot{\mathrm{Cl}}+\dot{\mathrm{C}} l \rightarrow \mathrm{Cl}-\mathrm{Cl}\)
c) \(\dot{\mathrm{C}}_3+\mathrm{Cl}_2 \rightarrow \mathrm{CH}_3-\mathrm{Cl}+\dot{\mathrm{Cl}}\)
d) \(\mathrm{Cl}_2 \rightarrow 2 \dot{\mathrm{Cl}}\)
e) \(\mathrm{CH}_4+\dot{\mathrm{Cl}} \rightarrow \dot{\mathrm{C}} \mathrm{H}_3+\mathrm{HCl}\)
f) \(\mathrm{CH}_3+\dot{\mathrm{C}}_3 \rightarrow \mathrm{CH}_3-\mathrm{CH}_3\)

1. A \(\begin{array}{cc}
   \underline{X} & \underline{Y} \\
   \text { c, d } & \text { a, b }
   \end{array}\)
2. B \(\begin{array}{cc}
   \underline{X} & \underline{Y} \\
   \text { b, d } & \text { a, c, e } \\
   \end{array}\)
3. C \(\begin{array}{cc}
   \underline{X} & \underline{Y} \\
   \text { d, e } & \text { b, c, f } \\
   \end{array}\)
4. D \(\begin{array}{cc}
   \underline{X} & \underline{Y} \\
   \text { d } & \text { a, b, f }
   \end{array}\)