Journalize the adjusting entry needed on December 31, 2017, the end of the current accounting period, for each of the following independent cases affecting Callaway Corp. Include an explanation for each entry.

a. Details of Prepaid Insurance are shown in the account:

Callaway prepays insurance on March 31 each year. At December 31, $900 is still prepaid.
b. Callaway pays employees each Friday. The amount of the weekly payroll is $6,000 for a five-day work week. The current accounting period ends on Wednesday.
c. Callaway has a note receivable. During the current year, the company has earned accrued interest revenue of $500 that it will receive next year.
d. The beginning balance of Supplies was $2,600. During the year, Callaway purchased supplies costing $6,100, and at December 31 the cost of supplies on hand is $2,100?
e. Callaway is providing financial services for Manatawabi Investments Inc., and the owner of Manatawabi paid Callaway $12,000 for its annual service fee. Callaway recorded this amount as Unearned Service Revenue. Callaway estimates that it has earned one-third of the total fee during the current year.
f. Depreciation for the current year includes Office Furniture, $1,000, and Equipment, $2,700. Make a compound entry.

Prepaid Insurance Jan. 400 Mar. 31 3,600