Final answer:
In a peer-to-peer network, the two roles a computer can assume when a file is being shared are client and server. There is no master-slave relationship in this type of network, and 'transient' is not a role.
Step-by-step explanation:
In a peer-to-peer network where a file is being shared between two computers, each computer can assume one of two roles: either a client or a server. As a client, a computer requests data from another computer. As a server, it provides data to another computer. A master-slave relationship typically does not exist in a peer-to-peer network, where all nodes are considered equal and there is no centralized control. The term transient is not typically used to describe a role of a computer in a network context.