Which of the Following Statements Concerning Practical Standards Is Incorrect

Which of the following statements concerning practical standards is incorrect?

A) Practical standards can be used for product costing and cash budgeting.
B) Practical standards can be attained by the average worker.
C) When practical standards are used, there is no reason to adjust standards if an old machine is replaced by a newer, faster machine.
D) Under practical standards, large variances are less likely than under ideal standards.