What is key difference between a set and a list?

1.  A set is an ordered collection unique items. A list is an unordered collection of non-unique items.
2.  Elements can be retrieved from a list but they cannot be retrieved from a set.
3.  A set is an ordered collection of non-unique items. A list is an unordered collection of unique items.
4.  A set is an unordered collection unique items. A list is an ordered collection of non-unique items.

Correct Answer:

•  A set is an unordered collection unique items. A list is an ordered collection of non-unique items.