John Pickens Writes Mystery Novels

John Pickens writes mystery novels. His publisher pays him royalties for the number of books sold each year. He is paid royalties for the first half of the year on September 30 and the second half of the year on March 31 of the following year. He received $42,000 in September, 2018. The publisher estimated that his royalties for the second half of the year would be $53,000. On March 31, 2019, he received $57,500. Assuming that he recorded $53,000 in royalties at December 31, 2018, what kind of change does this represent?

A) not a change
B) change in estimate
C) prior period error correction
D) change in accounting principle