以下能实现将变量first_name、字符串" "和变量last_name合并后保存在变量full_name中的程序是
A.
first_name="jimmy" last_name="carter" full_name=first_name+" "+last_name
B.
first_name="jimmy" last_name="carter" full_name=last_name+" "+first_name
C.
first_name="jimmy" last_name="carter" last_name+" "+first_name=full_name
D.
first_name="jimmy" last_name="carter" last_name=last_name+" "+first_name