When Using a Standard Costing System,which of the Following Statements

When using a standard costing system,which of the following statements is true?

A) There is never any question about the recorded cost of a unit in inventory; it is always at the standard cost.
B) There is always a question about the recorded cost of a unit in inventory; the standard cost differs with each purchase.
C) A unit recorded in inventory last week and one recorded in inventory today will not have the same recorded cost.
D) None of these ans choices are true.