Required: For each situation, describe the cost as one of the following: fixed cost, variable cost, mixed cost, or step cost. A. The salary of a legal secretary in a law firm. Fixed B. A lease contract for an automobile which requires a monthly payment of $300 plus $.05 per mile. Variable C. The cost of lumber for a homebuilder. Fixed D. The cost of Internet service which is calculated based on hours of usage. Fixed E. The cost of telephone service, which includes a fixed monthly charge of $50 plus $.10 a minute for long-distance calls. Variable F. The salary cost of seasonal tax preparers for a CPA firm; One tax preparer can prepare 100 tax returns per month. G. A factory supervisor's salary. H. The cost of sugar in the production of soft drinks