What is list comprehension in Python?

List comprehension in Python is a concise and powerful way to create lists in a single line of code. It allows you to build a new list by applying an expression to each item in an existing iterable, such as a list or a range, and can also include a condition to filter items. This not only streamlines code and enhances readability but also can lead to more efficient coding practices.

For example, instead of using a loop to create a new list where each element is the square of numbers in an existing list, list comprehension allows you to do this succinctly:

squares = [x**2 for x in range(10)]

This single line replaces a more verbose loop, making it clear and easier to understand at a glance.

The other choices do not accurately describe list comprehension's purpose or functionality. Creating tuples quickly is not the focus of list comprehension, nor does it involve merging lists or sorting them. Thus, option B captures the essence of what list comprehension is designed to do in Python.