Alandmark case is one that

a.

deals with disputes over states’ borders and water rights

b.

addresses real estate deals and stock market investments

c.

deals with a case that must be heard immediately because it is literally a matter of life or death

d.

addresses a pressing issue of the day and whose decision dramatically affects the nation

"A landmark case is a court case that is studied because it has historical and legal significance. The most significant cases are those that have had a lasting effect on the application of a certain law, often concerning your individual rights and liberties."

Therefore the answer would be "D) Addresses a pressing issue of the day and whose decision dramatically affects the nation " I think