The method used to obtain alcohol from molasses is called fermentation. Fermentation is a metabolic process in which yeast or bacteria convert sugars into alcohol and carbon dioxide. In the case of obtaining alcohol from molasses, the sugar present in molasses is converted into alcohol through the fermentation process.

Option 1: Distillation is a process used to separate components based on their different boiling points. While distillation may be used in the production of alcohol, it is not the specific method used to obtain alcohol from molasses.

Option 2: Hydrolysis is a chemical reaction in which a compound is broken down into simpler compounds by reacting with water. Hydrolysis is not the method used to obtain alcohol from molasses.

Option 4: Oxidation is a chemical reaction that involves the loss of electrons or an increase in oxidation state. Oxidation is not involved in the process of obtaining alcohol from molasses.

Therefore, the correct answer is option 3: fermentation.