Which of the following correctly swaps the values of variables A and B?

The correct option is A, B = B, A.

Here's why:

• A = B: This assigns the value of B to A. The original value of A is lost, and B remains unchanged. This does not swap the values.
• swap(A, B): This represents a function call. While a swap function might exist in some programming languages, it's not a universal syntax for directly swapping values without defining the function itself.
• A == B: This is a comparison operator that checks if A is equal to B. It does not perform any assignment or swap.
• A, B = B, A: This is a common syntax in several programming languages (like Python) for simultaneous assignment. The values on the right-hand side (B and A) are evaluated, and then assigned to the variables on the left-hand side (A and B) respectively, effectively swapping their values without needing a temporary variable.