​(Identifying spontaneous,​ temporary, and permanent sources of​ financing) Classify each of the following sources of new financing as​ spontaneous, temporary, or​ permanent: a. A manufacturing firm enters into a loan agreement with its bank that calls for annual principal and interest payments spread over the next four years. b. A retail firm orders new items of inventory that are charged to the​ firm's trade credit. c. A trucking firm issues common stock to the public and uses the proceeds to upgrade its tractor fleet.