Answer:
C) Debit Conversion cost $607,000 Credit Wages​ Payable, Accumulated​ Depreciation, etc. $607,000
Explanation:
First we understand what conversion cost is
Conversion cost represents the cost that is relevant and incurred when a  manufacturing organisation converts its obtained raw materials into its sell-able finished goods.
As such, what is the relevant conversion cost here
= The total conversion cost = Direct Labour + Overhead
= $600,000 + $7,000 = $607,000
Step 2: Since, wages were not paid, the account to use is wages payable, therefore the journal entry will be
Description                 Debit           Credit
Conversion Costs         $607,000
Wages Payable, Accumulated Depreciation etc  $607,000