Answer:
A. $20,000 under applied overhead
Step-by-step explanation:
Firstly, we start with determining the predetermined overhead rate.
Predetermined manufacturing overhead rate = Total estimated overhead cost for the period / Total amount of allocation base
= $600,000 / 300,000
= $2 per machine hours
Now, we can allocate overhead
Allocated MOH = Estimated manufacturing overhead rate × Actual amount of allocation base
= $2 × 315,000
= $630,000
Finally, the under/Over allocation
Under/Over applied overhead = real overhead - Actual overhead
= $650,000 - $630,000
= $20,000