One way you could try that is answer with the metaphorical meaning, see whether it's rejected, and if so, report it as "my answer should be accepted".
Then wait for a course contributor to look at the reports for that unit and decide whether to add it.
You could also comment in the sentence discussion in the hope that a course contributor happens to see the comment.
There are only three of us, and while we do try to be active, there's no guarantee we will see any given comment, so the report might be safer -- it might take longer but is less likely to simply get overlooked, because it doesn't "scroll off the page".
In this case I wasn't sure how to phrase the sentence best in English, to be honest. But the third option is sort of what I did, mentioning it here. In another, similar sentence, "What you said is obvious." was indeed accepted. I actually looked in boQwI' if "what you said" was included in the English version — and it was. :)
I also mentioned it here for learners to see.