Which of the following is the best argument for keeping the penny in circulation in the United States?

• It helps when adding sales tax, which often includes fractions.
• It has the face of a very accomplished president.
• It costs more than a penny is worth to manufacture one.
• It would help marketing to have every price end in a 0 or 5.

The best argument for keeping the penny in circulation in the United States is that it helps when adding sales tax, which often includes fractions. Having the penny allows for more precise transactions, especially when dealing with sales tax that may result in cents when rounding. This ensures that customers are paying the correct amount for their purchases.