Choice "C" is correct. Guess may use estimates provided by Bates if it is not practical for Bates to obtain exact data. Choice "b" is incorrect. The preparer (Guess) may use estimates provided by the taxpayer (Bates) if it is not practical for the taxpayer to obtain exact data. However, the preparer must determine that the estimates are reasonable based on the facts and circumstances.Choice "a" is incorrect. It is normally not necessary to disclose the use of estimates. Disclosure of estimates should be made in unusual circumstances, such as when records have been destroyed. However, there is no "Estimates Have Been Used in the Preparation of this Return" box.Choice "d" is incorrect. Guess may use estimates provided by Bates if it is not practical for Bates to obtain exact data. The number of years that Guess has been preparing Bates' returns is not relevant.