Which of the following correctly demonstrates a variable assignment in Python?

In Python, variable assignment is performed using the equals sign (=). This sign assigns the value on the right to the variable named on the left. Therefore, when you see x = 5, it means that the integer value 5 is assigned to the variable x, allowing you to use x later in your code to refer to that value.

The other choices reflect incorrect syntax for variable assignment in Python. For instance, saying 5 = x attempts to assign a variable to a literal value, which is not valid. The use of := is known as the "walrus operator" but is used within specific contexts like assignments within expressions, not as a standard variable assignment. The notation assign(x, 5) suggests a function call rather than a direct assignment, which is not how variables are typically assigned in Python.

Thus, x = 5 correctly illustrates how to assign the value 5 to the variable x in Python.