设有一结构体类型变量定义如下：structdate{intyear;intmonth;intday;};structworker{charname[];charsex;structdatebirthday;}w;若对结构体变量w的出生年份进行赋值，下面正确的赋值语句是（）Ayear=Bbirthday.year=Cw.birthday.year=Dw.year=