酶与一般催化剂比较所特有下列哪项性质？（）

A.酶在反应前后无质和量的变化

B.只加速反应进程不改变反应的平衡点

C.机制是降低反应的活化能

D.只促进热力学允许的反应

E.对反应底物有专一性

Originally introduced by Netscape Communications, (1) are a general mechanism which HTFP Server side applications, such as CGI (2) , can use to both store and retrieve information on the HTTP (3) side of the connection. Basically, Cookies can be used to compensate for the (4) nature of HTTP. The addition of a simple, persistent, client-side state significantly extends the capabilities of WWW-based (5) .

（3）是（）

A.Client

B.Editor

C.Creator

D.Server