Required Identify the following costs as fixed or variable: Costs related to plane trips between Boston, Massachusetts, and San Diego, California, follow. Pilots are paid on a per-trip basis. a. Pilots' salaries relative to the number of trips flown. b. Depreciation relative to the number of planes in service. c. Cost of refreshments relative to the number of passengers. d. Pilots' salaries relative to the number of passengers on a particular trip. e. Cost of a maintenance check relative to the number of passengers on a particular trip. f. Fuel costs relative to the number of trips. Metro National Bank operates several branch offices in grocery stores. Each branch employs a supervisor and two tellers. Costs related to Metro's branch operations follow. g. Tellers' salaries relative to the number of tellers in a particular district, which is composed of branches. h. Supplies cost relative to the number of transactions processed in a particular branch. i. Tellers' salaries relative to the number of customers served at a particular branch. j. Supervisors' salaries relative to the number of branches operated. k. Supervisors' salaries relative to the number of customers served in a particular branch. I. Facility rental costs relative to the size of customer deposits. Costs related to operating a fast-food restaurant follow