What is the difference in the short run and the long run? in the short run, a. at least one of the firm's inputs is fixed, while in the long run, the firm is either able to vary all its inputs, adopt new technology, or change the size of its physical plant. b. at least one of the firm's inputs is fixed, while in the long run, at least one of the firm's inputs is variable. c. all of the firm's inputs are fixed, while in the long run, the firm is able to vary all its inputs, adopt new technology, and change the size of its physical plant. d. at least one of the firm's inputs is fixed, while in the long run, the firm is able to vary all its inputs, adopt new technology, and change the size of its physical plant. e. all of the firm's inputs are variable, while in the long run, the firm is able to vary all its inputs as well as adopt new technology and change the size of its physical plant?