On June 1, 2019, Enne Brahtz Corporation Received $10,800 as Advance

On June 1, 2019, Enne Brahtz Corporation received $10,800 as advance payment for 12 months' advertising. The receipt was recorded as a credit to Unearned Fees.
What adjusting entry is required on December 31, 2019?

A) Advertising Revenue 6,300
$\quad$ $\quad$ $\quad$ Unearned Fees 6,300
B) Unearned Fees 5,400
$\quad$ $\quad$ $\quad$ Advertising Revenue 5,400
C) Unearned Fees 4,500
$\quad$ $\quad$ $\quad$ Advertising Revenue 4,500
D) Unearned Fees 6,300
$\quad$ $\quad$ $\quad$ Advertising Revenue 6,300