Which of the following statements is true about the source Message Structure?

The statement that the source Message Structure selects a subset of fields for a specific message type is correct because it highlights the core functionality of the source Message Structure within the Avaloq Message Interface (AMI). In the context of AMI, the source Message Structure is designed to tailor messages depending on their type, ensuring that only relevant fields are included. This selective process allows for efficient message processing and communication, aligning the content of the message closely with the requirements of its specific context or use case.

By focusing on a particular set of fields for each message type, the source Message Structure aids in maintaining clarity and reducing unnecessary complexity, which enhances both the creation and interpretation of messages. This capability is fundamental to effective message handling in systems that rely on structured data exchanges. The other options do not accurately represent the role of the source Message Structure; for example, it is not irrelevant to message formatting or lacking in structural guidelines, as these aspects are integral to its functionality.