Supplies originally cost $600, but only $150 worth of supplies were used this period. The adjusting entry would be Oa. debit Supplies Expense, $450; credit Supplies, $450. Ob. debit Supplies Expense, $150; credit Supplies, $150. Oc. debit Supplies, $450; credit Supplies Expense, $450. Od. debit Supplies, $150; credit Supplies Expense, $150