QUESTION 12 Which of the following is not a required characteristic for a function U(.) to be considered a valid utility function? (Select all that apply) A. For any two bundles, A and B, either U(A) ≥ U(B) or U(B) ≥ U(A) must be true B. For any three bundles, A, B, and C, if U(A) ≥ U(B) and U(B) ≥ U(C), then U(A) ≥ U(C) C. U(.) must be monotonically increasing in all possible bundles D. U(.) must be able to assign a utility to every possible bundle of goods