已知字符串str = "Happy birthday"，则执行print(list(str))的输出结果是？（ ）
['H','a','p','p','y','b','i','r','t','h','d','a','y']
[H,a,p,p,y,b,i,r,t,h,d,a,y]
['H','a','p','p','y',' ','b','i','r','t','h','d','a','y']
[H,a,p,p,y, ,b,i,r,t,h,d,a,y]
