The correct response to the question about the differences between a sales tax and a use tax is:
A sales tax is on the purchase of goods and services at the point of sale while a use tax is paid on goods and services purchased when sales tax was not paid.
This distinction highlights that sales tax is typically collected at the time of purchase, while a use tax is applied to goods and services that were bought without paying sales tax, often applicable to items purchased out of state or online.