Mason, an accrual basis taxpayer, owns a six-unit apartment building for which he receives rent of $600 per month per unit. In 2009, five of the units were rented for the entire twelve-month period. The sixth unit was occupied from January 1st through March 31st. Upon vacating the unit, the tenant was not refunded his security deposit of $400 due to damages to the unit. The unit was subsequently rented for one year beginning August 1, 2009. On August 1st, the new tenant paid the first and last month's rent and a refundable security deposit of $400. What is Mason's total rental income for 2009?
a. $40,800
b. $41,200
c. $41,800
d. $42,200