Which of the following is a characteristic of a well-defined system requirement?It is subject to frequent changes.It is vague and open to interpretation.It is complex and difficult to understand.It is clear, concise, and testable.

The characteristic of a well-defined system requirement is that it is clear, concise, and testable.

Here's why:

1. Clear: A well-defined system requirement is clear, meaning it is easy to understand and leaves no room for ambiguity. Everyone involved, from the project team to the stakeholders, should have the same understanding of what the requirement means.

2. Concise: A well-defined system requirement is concise, meaning it is brief but comprehensive. It should contain all the necessary information without being overly wordy or complicated.

3. Testable: A well-defined system requirement is testable, meaning it can be verified. There should be a way to check if the requirement has been met or not. This is crucial for quality assurance and for ensuring the system meets the users' needs.

On the other hand, a requirement that is subject to frequent changes, vague and open to interpretation, or complex and difficult to understand is not well-defined. Such requirements can lead to confusion, misinterpretation, and problems in system development and implementation.