Tuples in Python

Tuples in Python are immutable ordered collections of elements. They are similar to lists, but unlike lists, tuples cannot be modified once they are created. Tuples are defined using parentheses and elements are separated by commas. For example:

```
my_tuple = (1, 2, 3, 4)
```

Statement: Tuples can be used as keys in a dictionary

The correct answer to the given question is option 'C': Tuples can be used as keys in a dictionary. This means that tuples can be used as the key when creating a dictionary in Python.

Explanation:

Dictionaries in Python are key-value pairs, where each key is unique. The keys in a dictionary must be immutable, meaning they cannot be changed. Since tuples are immutable, they can be used as keys in dictionaries.

When a tuple is used as a key in a dictionary, it provides a unique identifier for a specific value. This allows for efficient lookup and retrieval of values associated with the tuple keys.

For example, let's say we want to create a dictionary that stores the population of different cities. We can use tuples to represent the city and its population as key-value pairs:

```python
population_dict = {('New York', 'USA'): 8623000, ('Tokyo', 'Japan'): 13929286}
```

In this example, the tuples ('New York', 'USA') and ('Tokyo', 'Japan') are used as keys, and the corresponding population values are stored as the dictionary values.

Tuples are suitable as keys in dictionaries because they are immutable. If tuples were mutable, it would be possible to change their values, which would lead to inconsistencies in the dictionary. Therefore, tuples provide a reliable and efficient way to represent unique keys in dictionaries.

Conclusion:

In conclusion, the statement that is true about tuples in Python is that tuples can be used as keys in a dictionary. Tuples are immutable, ordered collections of elements, and they provide a reliable and efficient way to represent unique keys in dictionaries.