A client/server implementation approach in which any platform may act as a client or server or both
is called:

A.
Peer-to-peer

B.
Simple file transfer

C.
Graphical User Interface (GUI)

D.
Application Programming Interface (API)

Explanation:
In answer Simple file transfer, a workstation or PC uses terminal emulation software and a client
application program to receive data from a host machine. For answer API, an API defines how the
client and server appear to each other and supports the exchange of information without either
entity knowing the details of a particular resource that is accessed using the API. One example is the
Generalized Security Application Programming Interface (GSAPI) that applications can use to access
security services. Answer GUI, the GUI approach, is similar to the API implementation and employs a
user interface such as SQL to access a server database.