Compound X has the molecular formula C6H10. X decolorizes bromine in carbon tetrachloride. X also shows IR absorption at about 3300 cm-1 . When treated with excess hydrogen and a nickel catalyst, X yields 2-methylpentane. The most likely structure for X is:

The correct answer is - option D. (check image)

Explanation:

Alkynes and alkenes both decolorized bromine in carbon tetrachloride. The absorption of the IR at about 3300 cm-1 for the X here that are found in the terminal alkynes absorption range only. In presence of excess hydrogen and a nickel catalyst, x gives the  2-methyl pentane.

The most likely structure for X is: CH3-CH3-ch-CH2-C≡CH