An organisation has the following total costs at two activity levels:

Activity level (units) 16,000 22,000

Total costs ($) 135,000 170,000

Variable costs per unit is constant within this range of activity but there is a step up of $5,000 in the total fixed costs when the activity exceeds 17,500 units.

What is the total cost at an activity level of 20,000 units?

A $163,320 B $158,320 C $160,000 D $154,545