Cindy has entered into a binding agreement to sell a house to Bobby. When Bobby shows up to complete the deal as per the agreement, Cindy refuses to go through with the transaction. Which of the following best categorizes Cindy and Bobby's issue in the context of classifications of laws?

This is a private law issue regarding criminal law.

This is a private law issue regarding contract law.

This is a public law issue regarding property law.

This is a public law issue regarding tort law.

This is a public law issue regarding substantive law.