下面有一段JavaScript程序,其输出结果是()。var str = "I am loser, you are loser, all are loser.";var str_new = str.replace("loser", "hero");document.write(str_new);
A. I am hero, you are hero, all are hero.
B. I am "hero", you are "hero", all are "hero".
C. I am hero, you are loser, all are loser.
D. I am "hero", you are loser, all are loser.