Traceability matrix, AFAIK, is from Requiements to Defect.
So, take the corrosponding requirement for the date field, map it to the design feature, map the design to the source code, map the source code to the test case list that tests it and this to the defect ID.
Am sure you'd be having many IDs to do this mapping. Hope this helps.
Secondly, do a google for CMMi 5 and requirement traceability matrix and that should give you a lot of pointers, if the above does not help!!!
- Fake Software Tester
(Not a secret identity, but a chosen mask!!!)
A requirements traceability matrix (tying requirements to test cases) is by far my least favorite artifact on the face of the Earth. We're essentially talking about creating an association table-- if you're doing this manually (i.e. with Excel) then creating the document itself is the least of your problems.
Don't get me wrong-- the information that you'd use to build such an artifact is essential-- but definitely use a tool to manage this mapping. I have a really hard time getting useful information out of an excel sheet that is 20 miles long with columns like "Sr. No.", "Requirement ID" and "Test Case ID"... I'd spend all day doing something that should be 2 clicks in a free/open source (or cheap) test management tool.
Resist the urge to do it just for compliance's sake! Implement a tool to do this for you.
As far as how you'd answer such a question in an interview-- this is really not a great interview question to start with-- hopefully they are just trying to see if you are familiar with the concept of tying requirements to tests. If you have a requirement or two that were written about this text box, then those requirements would show up in your RTM, indicating which test cases cover those requirements.