Credible Promises and Hostage Mechanisms Can Support a Continuous Stream

Multiple Choice

Credible promises and hostage mechanisms can support a continuous stream of cooperative exchanges except when

A) the promisor is better off fulfilling than ignoring his promise
B) neither party has a prior dominant strategy
C) the hostage can be revoked for just causes
D) the hostage is more valuable than any given exchange
E) the hostage is difficult to replace