Electronic Data Interchange Software consists of the following four layers :

Answer: Business application, Internal format conversion, EDI translator, EDI envelope.

Explanation: The four EDI software layers and their roles are:

• Business application: The source or destination application that generates or consumes business documents.

• Internal format conversion: Converts application-specific data to and from a standard internal EDI format used for translation.

• EDI translator: Performs mapping, validation and conversion between the internal EDI format and the interchange/syntax formats.

• EDI envelope: Packages EDI messages with headers and trailers for routing and transmission.

Why the other listed combinations are incorrect:

• "Business application, Internal format conversion, Network translator, EDI envelope" is incorrect because "Network translator" is not the standard EDI layer name; the proper layer is the EDI translator that handles mapping and validation.

• "Application layer, Transport layer, EDI translator, EDI envelope" is incorrect because it uses network-layer terminology (application/transport) rather than EDI software layer names and omits internal format conversion.

• "Application layer, Transport layer, IP layer, EDI envelope" is incorrect because it mixes networking stack layers with an EDI envelope and omits the essential internal format conversion and EDI translator layers.