The one contract that is not in violation is:
b. contract that is based on usury interest rates
Step-by-step explanation:
The violation of the legality element of a contract means the enforcing ability of a contract in lieu of the existing rules that define the legality or illegality of a contract that is drawn up between two parties.
The options given here violate one common law or another for the drawing up contract except for the usury rates.
Usury interest rates are the standard accepted rates for money in contracts and one that follows the rates is legal and can be enforced.