which is the best reason for why an American manager working abroad might make more money than a manager who was hired locally

American managers are usually more skilled than managers from other countries
american managers work harder than foreign managers
american managers should expect more pay because they are american
american managers may be subject to different compensations laws

The best reason for why an American manager working abroad might make more money than a manager who was hired locally is that American managers may be subject to different compensations laws.