Which of the following is NOT true for variable manufacturing overhead costs in a standard costing system?

Multiple Choice

a$.$ No volume variance is ever reported.

b$.$ The flexible variable overhead allowance for the standard hours allowed for the output is the same as the applied total variable overhead.

c$.$ The slope of the budgeted variable overhead line is the same as the slope of the applied variable overhead line.

d$.$ Any underapplied or overapplied overhead is equal to the variable overhead spending variance.