Best Company adjusts and closes its accounts at the end of each month. The trial balance at end of the March 2021 , before adjustments, is as follows: The following information relates to month end adjustments: (a) Office supplies on hand amounted to $500. (b) The useful life of the equipment was estimated to be 7 years with no salvage value. (c) Many clients pay in advance. Fees of $6,000 were earned during the month by performing contracts for clients who had paid in advance. (d) Salaries earned by employees during the month but not yet recorded amounted to $2,300. (e) On the first of the month, Best Co. moved in paid 3 month's rent in advance. (f) Contracts completed during the month but not yet billed or recorded amounted to $4,600. Prepare the adjusting entries required at end of the month