The XMLToJSON policy is the most appropriate choice for converting a SOAP response to a JSON response. SOAP (Simple Object Access Protocol) messages are fundamentally structured in XML format. The XMLToJSON policy is specifically designed to parse an XML payload, such as a SOAP message body, and transform it into a corresponding JSON structure. This policy provides various options to control the conversion process, handling XML elements, attributes, and text content to produce a well-formed JSON output, making it the best tool for this specific task.

A. AssignMessage: This policy creates or modifies messages but does not have built-in logic for format transformation between XML and JSON.

B. Message Validation: This policy is used to validate message formats against a schema (e.g., XSD or JSON Schema), not to convert them.

C. SOAPToJSON: This is not a standard, existing policy type within the Google Apigee platform; it is a plausible but incorrect distractor.

1. Google Cloud Apigee Documentation

"XML to JSON policy": "The XMLtoJSON policy lets you convert messages from the Extensible Markup Language (XML) format to JavaScript Object Notation (JSON)." This directly confirms that XMLToJSON is the correct policy for converting XML-based messages like SOAP into JSON.

Source: Google Cloud

Apigee Documentation

Policy reference

XML to JSON policy.

2. Google Cloud Apigee Documentation

"Assign Message policy": "The AssignMessage policy changes or creates new request and response messages during an API proxy flow. It lets you perform...Set the payload of a message." While it can set a payload

it does not perform the complex logic of format conversion itself.

Source: Google Cloud

Apigee Documentation

Policy reference

Assign Message policy.

3. Google Cloud Apigee Documentation

"Message Validation policy": "The MessageValidation policy validates a request or response message against a defined schema...For XML messages

Apigee uses the XML Schema Definition (XSD)." This clearly defines its purpose as validation

not transformation.

Source: Google Cloud

Apigee Documentation

Policy reference

Message Validation policy.

4. Google Cloud Apigee Documentation

"Policy reference overview": A review of the complete list of available policies in the official Apigee documentation confirms that a policy named SOAPToJSON does not exist.

Source: Google Cloud

Apigee Documentation

Policy reference overview.