What does the speaker mean

A．Everyone has more enthusiasm than she does.

B．She’s the most enthusiastic person I know.

C．She’s no more enthusiastic than the others.

D．Nobody has any enthusiasm in the promotion.

1971年联合国教科文组织在“人与生物圈计划”研究中提出的概念是

A．可持续发展城市

B．环保城市

C．生态城市

D．绿色城市