What is the purpose of the `len()` function in Python?

The len() function in Python is used to return the number of items in an object. This function is applicable to various data types, including strings, lists, tuples, and dictionaries. When called, len() provides an integer that indicates how many elements or characters are present in the specified object.

For instance, if you apply len() to a string like "Hello", it returns 5 because there are five characters in that string. Similarly, calling len() on a list such as [1, 2, 3] will return 3, reflecting the three items contained in the list. This utility makes len() very important for determining the size of sequences or collections, which is crucial in many programming scenarios, especially in loops or conditional statements where you need to know how many items you are working with.

The other choices do not represent the function or purpose of len() accurately. A function to calculate memory size would involve more complex measures and tools, while creating an object and clearing contents would not relate to counting items. Thus, the correct understanding of the len() function aligns with the choice that states it returns the number of items in an object.