X Company used the high-low method with information from April and September, to predict monthly factory costs. In April, factory costs were $7,851, and 2,300 units were produced. In September, factory costs were $13,251, and 5,000 units were produced. What are estimated total variable factory costsin December, when the company expects to produce 3,500 units?

A: $7,000

B: $10,150

C: $14,718

D: $21,340

E: $30,944

F: $44,868