Notice on the spreadsheet, the amount of capital in the spreadsheet stays constant at 4 while the amount of labor varies from 0 to 30. Choose all that are correct a. The constant amount of capital denotes that the spreadsheet represents short term production because in the short run capital is fixed. b. The short run is defined as a period of time short enough that the quantity of at least one input used in the production process cannot be varied. c. In the short run, the only way for the firm to increase or decrease output is to vary the amount of the variable input. d. None of the answers are correct.