Which of the following is (are) true regarding cost flow assumptions?
a. Manufacturing firms are required to use FIFO.
b. Service firms are required to use LIFO.
c. If a firm uses FIFO for tax purposes, then FIFO must be used for financial reporting purposes.
d. If a firm uses LIFO for tax purposes, then LIFO must be used for financial reporting purposes.
e. All of these.