In which of the following data type, duplicate items are not allowed?.listSetDictionaryNone

To determine which data type does not allow duplicate items among the given options (list, set, dictionary, none), let’s analyze each data type:

1. List: A list is an ordered collection that allows duplicates. You can have the same item multiple times in a list.

2. Set: A set is an unordered collection that inherently does not allow duplicate items. If you try to add a duplicate, it will simply be ignored.

3. Dictionary: A dictionary is a collection of key-value pairs. While keys must be unique (duplicates are not allowed), values can be duplicated.

4. None: This option does not apply as it doesn't represent a data type.

Final Answer

The correct answer is Set, as it disallows duplicate items.