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

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.