4 For the following questions, select the key term that best matches with the definition provided. - The sum total of all the firm's fixed and variable costs at each level of output - The implicit cost of fixed resources used to produce a good or service - Total of the costs of all the variable resources used in production - A firm's total value of output, obtained by multiplying the units of product produced by the price of that product A. Total revenue B. Total variable cost C. Total fixed cost D. Total cost