Which of the statement(s) is/are correct?

1. In Python dictionary, the key-value pair is called an item.
2. Python dictionary is a mapping of unique keys to values.
3. Dictionary is mutable.
4. All of these.

To create an empty dictionary, we use the statement as:

1. d1 = {}
2. d1 = []
3. d1 = ()
4. d1 == {}

Keys of a dictionary must be:

1. Similar
2. Unique
3. Both (i) and (ii)
4. All of these

To create a new dictionary with no items:

1. Dict
2. dict()
3. d1={}
4. Both 2 and 3