The correct option is A Butanol
The nomenclature of hydrocarbon containing functional group is done as:
Prefix + Word root + Primary suffix + Secondary suffix
The given compound has four carbon atoms. Therefore, the word root is ‘but’.
All the bonds between C-C atoms in the given compound are single bonds. The hydrocarbons consisting only single bonds between C-C atoms are called alkanes. The primary suffix used for alkanes is ‘ane’.
The functional group present in the given compound is –OH. Therefore, it belongs to the family of alcohols. There is no prefix used in case of alcohols. The secondary suffix used for alcohols is ‘ol’. Therefore, the IUPAC name of the compound will be:
‘But’ + ‘ane’ + ‘ol’.
When secondary suffix starts with a vowel, last ‘e’ in the primary suffix is deleted. Now, the IUPAC name of the compound becomes:
‘But’ + ‘an’ + ‘ol’ = ‘Butanol’