Which of these situations would require auditors to append an emphasis-of-matter paragraph about consistency to an otherwise unmodified opinion?

a. Entity changed its estimated allowance for uncollectible accounts receivable.

b. Entity corrected a prior mistake in accounting for interest capitalization.

c. Entity sold one of its subsidiaries and consolidated six subsidiaries this year compared to seven last year.

d. Entity changed its inventory costing method from FIFO to LIFO.