Please include a quick explanation for me to better understand why, thank you!

Using information from the first graph below, we can tell that the firm's total cost curve is best represented by curve _____ in the second graph.

Units of capital 20- 18 - 16 14- Expansion path 12 10 8 O = 300 O = 220 O = 100 C =600 C = 1,200 C = 1,800 0 6 8 10 12 14 16 18 20 Units of labor Total cost ($) 2,000 - 1,800 1,600- 1,400 - 1,200- D 1,000 - 800 600 400 200- 0 50 100 150 200 250 300 350 Quantity of output