假设有个类已经定义了下述的变量:int num1=10; int num2=20; String word=new String("exam"); double answer=25.5;另外定义了以下方法头:public int stuff(String s, int x, int y)以下哪个是正确的方法调用? A. num1=stuff("hello",num1,num1); B. answer=stuff(word,answer,num2); C. num2=stuff("hello",num1,answer); D. num1=stuff(num1,num2,word);