_______ second hat doesn't fit me, either. Could I look at _______ third one?

A．A; a

B．The; the

C．A; the

D．The; a

“城市中各类人力资源保证了城市各项事业的发展对人才的需求”，这是何种城市生态学原理的体现( )

A．城市生态位原理

B．多样性导致稳定性原理

C．食物链(网)原理

D．系统整体功能最优原理