Hospitals, universities, labor unions, and other institutions may well have public purposes and be quite successful at achieving them even though each of their individual staff members does what he or she does only for selfish reasons. Which one of the following generalizations is most clearly illustrated by the passage? ['What is true of some social organizations is not necessarily true of all such organizations.', 'Often an instrument created for one purpose will be found to serve another purpose just as effectively.', 'Many social institutions have social consequences unintended by those who founded them.', 'An organization can have a property that not all of its members possess.']