Rum is primarily made from which plant?

Rum is primarily made from sugar cane, which is the primary source for the fermentation and distillation process that produces this spirit. Sugar cane juice, molasses (a byproduct of sugar production), or a combination of both can be utilized to create rum. This distinctive ingredient gives rum its characteristic sweet flavor profile, which can vary significantly based on the production method and the aging process.

In contrast, the other options refer to the main ingredients used in different types of spirits. Wheat is primarily used for vodka and some whiskies, rice is the main ingredient in certain types of sake and Asian spirits, and barley is mostly known for its role in the production of beer and whisky. Therefore, sugar cane is unique to rum, marking it as the correct choice for this question.