Categories Economics In perfect competition, specific sales tax effect the ____________ cost. Post author By thelooknow Post date March 24, 2022 A. Average fixed B. Marginal C. Both a & b D. None of the above CORRECT ANSWER IS: Marginal ← In perfect competition, the effect of profit tax is considered as the change in average _________ cost and _______________ tax. → In perfect competition and in short-run case, if specific sales tax is applied the MC (which is also the supply curve of the firm) curve will shift upward to the left, output will ________________ at the going price.