Answer: b) this is a private law issue regarding contract law
Explanation: Private law is the law and regulation that is present individuals and has no relation with the government. Contract law states about the law that contains the agreement rules and regulations for binding individual through it.
The situation mentioned in the question about Kate and Micheal states about the problem of private law that is related with contract law. In their situation the private law was made for selling the house of Kate to Micheal.But Kate is refusing to perform transaction process which is raising the issue in the contract law. As per the contract agreement Kate should sell the house to Micheal and by denying to do so , she is creating the issue.
Other options are incorrect because it does not consider government rules so it cannot be a public law.It cannot be substantive law as civil society's regulation and rules are not required in given situation
Criminal law is not related with the situation as crime activity is not involved and tort law is not defined as civil laws are not broken .Thus, the correct option is option(b).