How do you check if an item is in a list?

• A. Using the 'in' keyword.
• B. Using the 'exists' function.
• C. Using the 'find' method.
• D. Using the 'check' operator.

Answer: (A)

The 'in' keyword is the correct way to check if an item is present in a list in Python. When you use the 'in' keyword followed by the list, Python evaluates whether the specified item exists within that list and returns a boolean value of either True or False.

For example, consider a list defined as my_list = [1, 2, 3, 4, 5]. You can check if the number 3 is in the list by using the expression 3 in my_list. This will evaluate to True since 3 is indeed an element of the list.

The other choices do not accurately reflect how item membership is checked in Python. The 'exists' function is not built into Python; no such function is part of the standard library for checking membership in lists. Similarly, the 'find' method is used for strings, not lists, and it returns the index of the first occurrence of a substring or a specific value, rather than checking for existence directly in a list. Lastly, the 'check' operator does not exist in Python, thereby making it a non-viable choice for determining if an item is part of a list.