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

a.The company has signed a new union contract that increases the factory wages on average by $3.50 an hour.

b.Actual costs differed from standard costs for the preceding week.

c.The average price of raw materials increased from $4.68 per pound to $4.82 per pound.

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