In: Economics
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  | Marginal Physical Product of Variable Input  | Total  | Total  | 
  | 
(units)  | (units)  | (units)  | (units)  | (dollars)  | (dollars)  | (dollars)  | 
0  | 1  | 0  | $500  | $0  | ||
1  | 1  | 10  | (A)  | $500  | $200  | (F)  | 
2  | 1  | 25  | (B)  | $500  | $400  | (G)  | 
3  | 1  | 45  | (C)  | $500  | $600  | (H)  | 
4  | 1  | 60  | (D)  | $500  | $800  | (I)  | 
5  | 1  | 70  | (E)  | $500  | $1000  | (J)  | 
Refer to Exhibit 21-3. What level of output exhibits the lowest average total cost?
| a.45 units | 
| b.25 units | 
| c.10 units | 
| d.70 units | 
| e.60 units |