Sheffield, Inc. is a distributor of prepaid telephone cards to customers in its convenience stores. When Sheffield sells the cards, it then pays the telecommunications company, TeleExpress, less a commission of 20 percent of the selling price to customers. Sheffield receives $4,000 in cards in January 2020. Sheffield sold 50% of the cards in February, 30% in March, and 20% in April. It costs TeleExpress $3,060 to provide the telephone service on the cards sold by Sheffield. Indicate how much income Sheffield should recognize in January, February, March, and April. (If answer is 0, please enter 0. Do not leave any fields blank.) January income $ February income $ March income $ April income $