Option (i) is the answer.
Alcohols with the chemical formula can have a variety of structures.
A similar chemical formula may be used to make a total of four alcohols. Butan-1-ol, butan-2-ol, 2-Methylpropan-1-ol, and 2-Methypropan-2-ol are the compounds in question.
Only butan-2-ol possesses a chiral carbon atom (four distinct groups are linked to it).