Improper gains refer to the fact that benefits are obtained by non-statutory causes, causing losses to others. According to the above definition, what does the following not constitute A and B improperly profitable? ['It ’s raining a lot.', 'Reimbursement of RMB 20,000 for Party A.', 'On July 5, A and B entered into a contract to purchase rice. On July 10, A paid 20,000 yuan to B according to the contract. On July 15, B refused to pay for rice. On August 1, A unilaterally cancelled the contract.', 'A owes D 20,000 yuan. A mistakes B as D and repays 20,000 yuan to B.']