Fraud Investigators incorporated operates a fraud detection service. a. On March 31, 10 customers were billed for detection services totaling $27.000 b. On October 31, a customer balance of $1,600 from a prior year was determined to be uncollectible and was written off. c. On December 15 , a customer paid an old balance of $880, which had been written off in a prior year. d. On December 31,$520 of bad debts were estimated and recorded for the year. Required: 1. Prepare joumal entries for each transaction above. (if no entry is required for a transaction/event. seiect "No Journal Entry Requlred" in the first account fieid.)