On June 1, Puzzling Puzzles Company Sold Cari's Bookstore $17,200

On June 1, Puzzling Puzzles Company sold Cari's Bookstore $17,200 of puzzles for cash. During the month, Cari's Bookstore returned puzzles costing $2,000 to Puzzling Puzzles for a cash refund. In the same month, Cari's sold the remaining puzzles to their customers for a total of $20,400.
As a result of these transactions, at the end of the month, Cari's accounting equation will show a net:

A) Increase of Equity of $5,200
B) Increase of Assets of $20,400
C) Decrease of Assets of $15,200
D) Increase of Equity of $7,200