Final answer:
The amount of variable overhead that Duncanville applied is B. $160,000.
Step-by-step explanation:
The amount of variable overhead that Duncanville applied to production is $160,000 (Option B).
In the given information, it is stated that the fixed costs at zero production are $160.
As production increases, variable costs are added to the fixed costs to calculate the total cost.
Therefore, the variable overhead applied to production is the sum of fixed costs ($160) and variable costs.
Since there is no information given about the variable costs, we can assume that the variable overhead is equal to the fixed costs, which is $160,000.