Which of the following statements are true?

public class X
{
    public static void main(final String[] args)
    {
        String s1 = "abc";
        Object s2 = "ABC";
        s1.toUpperCase();
        System.out.println(s1.equals(s2));
    }
}
A) Compilation error.
B) Exception: "OperationNotSupportedException"
C) Output false.
D) Output true.
E) Output abc