The following show the total overhead costs for given levels of a company’s total output.
　　Cost ($)     output units
　　4 000       1 000
　　7 000       2 000
　　10 000       3 000
　　9 500       4 000
　　A step up in fixed costs of $ 500 occurs at an output level of 3 500 units.
 
　　What would be the variable overhead cost per unit (to the nearest $ 0.01 ) using the high-low technique?
　　A $1.67 per unit
　　B $1.83 per unit
　　C $2.75 per unit
　　D $3.00 per unit