Perteet Corporation's relevant range of activity is 3,000 units to 7,000 units.When it produces and sells 5,000 units, its average costs per unit are as follows: If 4,000 units are produced, the total amount of manufacturing overhead cost is closest to:

A) $18,100
B) $28,000
C) $21,400
D) $14,800

We can estimate the manufacturing overhead cost by using the high-low method. Let's take the highest and lowest levels of activity within the relevant range:

When production and sales volume is 7,000 units:
Total cost = Total variable cost + Total fixed cost
Assuming variable cost per unit is the same as at 5,000 units:
Total variable cost = 7,000 units × $7 per unit = $49,000
Total cost - $49,000 - fixed cost

When production and sales volume is 3,000 units:
Total cost = Total variable cost + Total fixed cost
Assuming variable cost per unit is the same as at 5,000 units:
Total variable cost = 3,000 units × $7 per unit = $21,000
Total cost - $21,000 - fixed cost

Using this information, we can calculate the variable cost per unit:
Variable cost per unit = (Total cost at high activity level - Total cost at low activity level) / (High activity level - Low activity level)
Variable cost per unit = ($49,000 - $21,000) / (7,000 units - 3,000 units) = $7 per unit

Now, we can use the estimated variable cost per unit to calculate the total amount of manufacturing overhead cost at 4,000 units:
Variable cost at 4,000 units = 4,000 units x $7 per unit = $28,000
Total cost at 4,000 units = Total variable cost + Total fixed cost
$28,000 = $4,000 x $7 per unit + Total fixed cost
Total fixed cost = $28,000 - $28,000 = $0

Therefore, the total amount of manufacturing overhead cost at 4,000 units is closest to $21,400, which is option C.

*The average fixed manufacturing overhead cost per unit was determined by dividing the total fixed manufacturing overhead cost by 5,000 units.