english legal system

Question: What does the term private law refer to?

a) The body of laws that derive from the deciding of cases
b) The body of laws that seek to regulate the relationship between individuals
c The legal principle that states that a person has the right to privacy
d) The body of laws that seeks to regulate the relationship between the state and its citizens

In the above question, I think option d) refers to criminal law.

Which types of laws do the other three options refer to and what are the key words that really suggest that this is the type of law that this option refers to.