In the Development of the Law of Negotiable Instruments, Which

In the development of the law of negotiable instruments, which of the following was not a step?

A) Centuries ago, contract rights to the payment of money were not assignable because the contractual promise ran to the promisee.
B) Contractual rights became assignable to third parties.
C) The law of assignments changed to permit assignees to obtain greater rights than their assignors.
D) The concept of a holder in due course developed, which allowed certain good faith transferees who gave value to acquire the right to be paid, free of most of the defenses to which an assignee would be subject.