Among the following hydrocarbons which one has acidic hydrogen?

Correct Answer: C. C2H3

Among the given hydrocarbons, the one that has an acidic hydrogen is: C2H3
In ethyne (C2H2), also known as acetylene, one of the hydrogen atoms is attached to a carbon atom in a triple bond (C≡C). The hydrogen attached to this carbon can be relatively acidic compared to typical hydrocarbons because the triple bond contains a high electron density in the vicinity of this hydrogen, making it more prone to being removed by a base in acid-base reactions.