The Connector Builder for Integration Service is a feature that enables the user to quickly add custom connectors to the tenant catalog in a no-code environment. The custom connectors can wrap any RESTful API and provide rich and scalable functionality on top of the original API1. The Connector Builder supports the following features:

REST APIs with JSON payload: The Connector Builder can connect to external systems that expose their API documentation as REST-compliant and both accept and return JSON2.

Various authentication types including OAuth 2.0 and API Key: The Connector Builder supports different types of authentication methods for the API calls, such as OAuth 2.0, Basic, Personal Access Token (PAT), API Key, etc3.

Building a connector from an API definition or from scratch: The Connector Builder allows the user to start building a connector from an existing API definition, such as a Swagger file, a Postman collection, or a URL, or from scratch by manually adding the API resources and methods4.

Option C is the correct answer, as it lists the features that the Connector Builder supports as defined in the documentation1. Option A is incorrect, because the Connector Builder does not support SOAP APIs or XML payloads, and it can build a connector from other sources besides a Swagger definition. Option B is incorrect, because the Connector Builder supports other authentication types besides OAuth 2.0 and Basic, and it can build a connector from other sources besides a Postman collection.Option D is incorrect, because the Connector Builder does not support SOAP APIs or XML payloads, and it supports other authentication types besides OAuth 2.0.