Unpaid and unrecorded invoices for utilities for December amounted to $1,500.

Iknow you debit Utilities expense, and my other options for credit are:
Cash
Accounts receivable
Supplies
Equipment
Accumulated depreciation
Accounts payable
Unearned revenue
Notes payab;e
Capital stock
Retained Earning.

well are we dealing with simple accounting journal entries I can see two possibilities depending upon how your accounts are structured but seriously this is a no-brainer for a beginner who has read a text book

clue for the clueless, when all else fails cash is the default