Explanation

(d)
Methyl iodide and ethyl iodide, on treatment with sodium in ethereal solution, give a mixture of propane, ethane and butane, as follows
$CH_{3}\boxed{I + 2Na + I} - CH_{2}CH_{3}$
$\overset{Ether}{\rightarrow}CH_{3}CH_{2}CH_{3} + 2NaI$
Propane
$CH_{3}I + 2Na + I - CH_{3} \rightarrow CH_{3} - CH_{3} + 2NaI$
ethane
$C_{2}H_{5}I + 2Na + I - C_{2}H_{5} \rightarrow C_{2}H_{5}C_{2}H_{5} + 2NaI$
butane