4 For the following questions, select the key term that best matches with the definition provided. - Units of output produced per unit of input for each level of variable input use - The value of output per unit of input for each level of variable input use - Productive resources (goods) that are available, as a result of past human decisions, to produce other want-satisfying goods - A constant input-output ratio A. Constant returns B. Capital C. Average value product D. Average physical product