Final answer:
The manager's operational efficiency ratio for this period is approximately 89.0%, based on the given attainable and actual product costs.
Step-by-step explanation:
To calculate the operational efficiency ratio, we need to divide the attainable product cost by the actual product cost and multiply by 100 to get the percentage. In this case, the attainable product cost is $29,000 and the actual product cost is $32,580.
Operational Efficiency Ratio = (Attainable Product Cost / Actual Product Cost) x 100
Operational Efficiency Ratio = ($29,000 / $32,580) x 100 = 89.04%
Therefore, the manager's operational efficiency ratio for this period is approximately 89.0% (option c).