—________ many buildings in your new school?

—Yes, ________.[ ]

A. Is there, there is              

B. Are there, there is

C. Is there, there are            

D. Are there, there are

《红楼梦》中“寿怡红群芳开夜宴”一章着力描写红楼儿女“怡红欢聚”的情形，请简要分析他们如此欢乐的原因。