—Mum, may I watch TV after supper?

—No, You _____ finish your homework first. [ ]

A. may

B. need

C. must

D. mustn't

《国家电网公司电能计量封印管理办法》中对卡扣式封印、穿线式封印、电子式封印安装位置是怎样规定的？