文登市境内的圣经山“东华宫”旧址上留有皇庆六年(1312)《东华帝君碑》一通,赵孟頫篆写了匾额。据此,你可以判断出《东华帝君》是哪个朝代的碑刻( )
A:北宋
B:元朝
C:隋朝
D:唐朝
_______ I walked into class, the teacher had started teaching already.