Answer:
The adjustment at month-end is :
Supplies Expense $400 (debit)
Supplies $400 (credit)
Explanation:
The Supplies Account is an asset Account that decreases as the supplies are used in the business.
The use of supplies prompts the recognition of an expense and de-recognition of an asset as follows :
Supplies Expense $400 (debit)
Supplies $400 (credit)