Suppose manufacturing overhead cost in manufacturing overhead control account is $12,000, manufacturing overhead cost under Work-in-Process account is $15,000. Period-end adjustment of manufacturing overhead using proration approach results in the ______ side change to the journal entry of COGS account, and a ______ operating income compared with write-off to COGS approach.

Credit; Lower

Credit; Higher

Debit; Lower

Debit; Higher