# The most abundant hydrogen pollutant is

$\begin{array}{1 1}(a)\;Ethane&(b)\;Methane\\(c)\;Propane&(d)\;Butane\end{array}$

The most abundant hydrogen pollutant is methane
The most abundant hydrocarbon in the atmosphere is methane, $CH_4$, released from underground sources as natural gas and produced from fermentation of organic matter.
Hence (b) is the correct answer.
edited Feb 21