Which of the Following Is Not a Reason That Actual

Which of the following is not a reason that actual direct labor costs may differ from the flexible budget amounts?

A) The purchasing manager resigned and a higher-paid replacement was hired.
B) After the company set the standard wage rate,the union reached an agreement that required a pay raise for all factory workers.
C) Because the air conditioner in the factory was not working properly,workers did not work as efficiently in the hot afternoons as expected.
D) All of these ans choices are correct.