Which statement is incorrect concerning allocation of production overhead? Select one: a. The allocation of fixed production overheads to the costs of production is based on the actual level of production b. Variable production overheads are allocated to each unit of production on the basis of the actual use of production facilities c. The amount of fixed overhead allocated to each unit of production is not increased as a consequence of low production or idle plant. d. Unallocated overheads are recognized as expense in the period in which they are incurred