ABC Corporation began operations on Sept. 1 by purchasing $6,000 of inventory and $600 of cleaning supplies. During the month, the company generated $7,500 of sales revenue. On Sept. 30, the company had $2,100 of inventory remaining, along with $400 of cleaning supplies. What was ABC Corporation's gross profit for the month of September? (Show your work for this problem, including labels for all numbers used in calculations.)