— Please tell Bruce he has won the first prize in the maths contest. 

—  ________! He never did so well before. [ ]

A. Good luck

B. Congratulations

C. That's right

D. What a good surprise

负荷管理是供电企业通过（）等经济手段，（）等技术手段引导用电移峰填谷，优化用电方式，提高负荷率。