Johnson, a landlord, receives the following receipts during the current year associated with his rental of apartments: Lessees' refundable deposits $ 3,000 Rent 10,000 Minor repairs and improvements made in lieu of rent 1,500 Prepaid rent 500 Pet deposits (nonrefundable) 400 What amount should Johnson report as taxable income from his rental investment? $12,000 $15,400 $10,900 $12,400