Select all that apply.

Which of the following four states were called the border states?

Maryland

Pennsylvania

Kansas

Kentucky

Missouri

Delaware

Virginia

Given no context as to what "border states" are, I am going to assume you are referring to the states that marked the border between the union and confederacy during civil war times. I believe that these states were as follows, Delaware, Kentucky, Maryland, Missouri, and West Virginia as it separated from Virginia at this time.