What is the result of the following program?

1: public class MathFunctions {
2: public static void addToInt(int x, int amountToAdd) {
3: x = x + amountToAdd;
4: }
5: public static void main(String[] args) {
6: int a = 15;
7: int b = 10;
8: MathFunctions.addToInt(a, b);
9: System.out.println(a); } }

❌ A. 10
✅ B. 15
❌ C. 25
❌ D. Compiler error on line 3.
❌ E. Compiler error on line 8.
❌ F. None of the above.

Explanation:
The code compiles successfully, so options D and E are incorrect. The value of a cannot be changed by the addToInt method, no matter what the method does, because only a copy of the variable is passed into the parameter x. Therefore, a does not change and the output on line 9 is 15.