To calculate the sales tax Bailey owes on her order, you can use the formula:
\[ \text{Sales Tax} = \text{Cost} \times \text{Sales Tax Rate} \]
Given the cost of the food and coffee is $21.25 and the sales tax rate is 9% (or 0.09 in decimal form), the calculation is as follows:
\[ \text{Sales Tax} = 21.25 \times 0.09 = 1.9125 \]
Rounding that to two decimal places, Bailey will owe approximately $1.91 in sales tax. Therefore, the correct response is:
$1.91