In which of the following situations would the account debtor NOT have to pay the assignee?

1. Albert (the account debtor) receives a letter stating that the $10,000 account he owes to Bud for catering services has been assigned to Clarence (the assignee). The letter was faxed to Albert on stationary with Bud’s masthead at the top, but the letter did not have Bud's signature on it.

2. Dwight (the account debtor) owes $20,000 to Eustace for services rendered. Dwight and Eustace agreed at the time of their contract that neither party was allowed to assign their rights to any other party. Regardless, Eustace later assigned his rights to Fredrick (the assignee), who has given notification to Dwight to pay the account to Fredrick.

3. George (the account debtor) employed Hamilton for a small construction project which ultimately cost $30,000, which George was required to pay in installment payments over the course of two years. George received a letter from Hamilton, both signed and dated, which stated the remaining balance of the account had been assigned to Ireland & June LLC (the assignee), a two person partnership that has equal rights in all accounts even upon termination of the partnership. Two months later, George received a letter from Ireland stating that Ireland and June no longer work together, the partnership no longer exists, and both parties have divided up the accounts and have agreed that George is now required to pay 50% of the remaining payments to Ireland and 50% to June.

4. Keith (the account debtor) hired Lucius to represent him in a personal injury case on contingency fee and no other payment is due. Lucius left the practice of law before the completion of the case and assigned all his accounts to Mortimer (the assignee), who works purely on an hourly fee rate. Keith consented to Mortimer representing him and signed an agreement that stated he would be charged hourly for all future work. No mention was made for work done by Lucius. The case resulted in no award to Keith. Keith paid Mortimer for the hours he spent on the case. Mortimer sent Keith an additional bill seeking additional payment for the hours which Lucius spent on the case.