Tobacco is typically sold by the _______ at auctions.

Tobacco is typically sold by the sheet at auctions because this form reflects the way tobacco is cultivated and prepared for sale. Sheets of tobacco represent a standard unit that aligns with the marketing and grading practices within the tobacco industry. Each sheet can vary in size and quality, which helps buyers assess the value and characteristics of the tobacco being auctioned.

In contrast, other options like boxes, pounds, or crates do not reflect the common practices in tobacco auctions. While crates might be used for packaging, they do not represent a standardized sale unit for the product itself. Similarly, pounds can relate to weight-based sales but aren't typically used as a unit for auction purposes, where the visual and qualitative assessment of the tobacco is critical.