The correct answer is C. single rate cost allocation method.
A single rate cost allocation method is a method of allocating support department costs to production departments that uses a single rate per unit of service provided. This method does not make any distinction between variable and fixed costs, and all costs are allocated using the same rate.
A dual-rate cost allocation method is a method of allocating support department costs to production departments that uses two rates: a variable rate and a fixed rate. The variable rate is based on the actual usage of the support department’s services by the production departments, and the fixed rate is based on the capacity of the support department.
A sales mix allocation method is a method of allocating support department costs to production departments that takes into account the different sales mixes of the production departments. This method is used when the support department’s costs are affected by the different sales mixes of the production departments.
A quantity variance allocation method is a method of allocating support department costs to production departments that takes into account the different quantities of products produced by the production departments. This method is used when the support department’s costs are affected by the different quantities of products produced by the production departments.