Which of the following is a true statement?

1) Essential features screen out possible solutions; mandatory features are the important capabilities of a system that will serve as the primary basis for comparison of different design strategies

2) Mandatory features screen out possible solutions; essential features are those that users could live without.

3) Essential features screen out possible solutions; mandatory features are those that users could live without.

4) Mandatory features screen out possible solutions; essential features are the important capabilities of a system that will serve as the primary basis for comparison of different design strategies

5) Desired features screen out possible solutions; mandatory features are the important capabilities of a system that will serve as the primary basis for comparison of different design strategies.