Which of the following conditions normally would indicate that standard costs should be revised?

A$.$ The Engineering Department has revised product specifications in responding to customer suggestions.

B$.$ The company has signed a new union contract that increases the factory wages on average by $$3\mathrm{.}50$ an hour.

C$.$ The average price of raw materials increased from $$4\mathrm{.}68$ per pound to $$4\mathrm{.}82$ per pound.

D$.$ all of these choices