The best answer here is the last one: Public and government acceptance. That is how paper money is "backed" in the USA. I hope this can help you a lot.
Answer:
The answer is oligarchy.
Explanation:
oligarchy was ruled by a few people and they had to be upper class and rich to rule.
The correct answer is nonrepudiation.
A nonrepudiation clause refers to a clause which forbids a person to challenge a particular contract he or she previously signed. According to this clause, once a person signs the contract, that is it - it is legally binding and cannot be challenged unless both parties agree to that. This clause can be found in an acceptable use policy.