【单选题】What is the purpose of the network layer of the OSI seven layer model?
A.
It selects a route for the message, forming segments into packets and adding the header information.
B.
It encodes the packets into the medium that will carry them - such as an analog signal, if the message is going across a telephone line - and sends the packets along that medium.
C.
It translates the message into a language that the receiving computer can understand.