在气相色谱法中，死时间为1分钟，某组分的保留时间为5分钟，其调整保留时间为（）。

A.1分钟

B.2分钟

C.3分钟

D.4分钟

E.5分钟

OSI is a theoretical model that shows how any two different systems can communicate with each other. Router, as a networking device, operate at the ______ layer of the OSI model.

A．transport

B．application

C．network

D．physical