Final answer:
The adjusting journal entry will lead to an increase in Supplies Expense and a decrease in Supplies, reflecting the use of supplies during the period and properly adjusting the assets and expenses on the financial statements.
Step-by-step explanation:
The adjusting journal entry described will have the effect of an increase in Supplies Expense and a decrease in Supplies. This adjustment is made to account for the use of supplies during the accounting period. When supplies are used, they're no longer available as an asset; thus, the Supplies account must be decreased to reflect this usage.
Simultaneously, the expense related to these supplies must be recognized in the period they were used, resulting in an increase in Supplies Expense. This adjustment ensures that the financial statements reflect the true costs and remaining assets of the business at the end of the accounting period. The correct answer is therefore (c), which matches standard accounting principles for recognizing expenses and adjusting assets.