How do you convert a string s to lowercase?

The method to convert a string to lowercase in Python is by using the lower() method, which is called on the string object itself. When you use s.lower(), it invokes the built-in lower() function associated with the string s. This function processes the string and returns a new string where all the uppercase letters have been converted to their corresponding lowercase letters.

In Python, calling s.lower() is a standard and efficient way to ensure that the contents of the string are represented in lowercase. This approach is integral to string manipulation within Python and conforming to object-oriented principles, as it operates directly on the string instance.

Other options do not represent valid methods for converting a string to lowercase in Python. For instance, lowercase(s) and toLower(s) do not exist as built-in functions or methods in Python. Similarly, str.lower(s) implies that lower() should be called as a function of the string class, which is incorrect; it should specifically be called on an instance of a string. Thus, the best practice and correct method for converting a string to lowercase in Python is indeed with s.lower().