3. Given a production function Q = 3LK, we can say that A) this production function is not Cobb-Douglas. B) this production function is Cobb-Douglas and exhibits decreasing returns to scale. C) this Cobb-Douglas production function does not exhibit a constant elasticity of substitution. D) this production function is Cobb-Douglas and exhibits increasing returns to scale. 4. Economic costs are synonymous with A) Accounting costs B) Sunk costs C) Opportunity costs D) Implicit costs