[Figure C] Which of the following best describes total cost at quantity QC?

A. Average Total Cost at QC divided by Quantity QC

B. Average Total Cost - Average Variable Cost at quantity QC

C. The marginal rate of technical substitution measured at QC

D. Average Total Cost at Quantity QC x QC

Cost MC AFC CD ATC Cc - - - - AVC CB CA Co AFC Qo QA QBec QD Quantity Figure C: Costs