Some writers say that when the question asks for a subject answer (as in Which form is the correct one? - This form is the correct one) rather than a complement answer (What's the time? - The time is eight o'clock), then there are two possible word orders:
Which form is correct?
1. Can you tell me which is the correct form?
2. Can you tell me which the correct form is.
If you are a learner, the safest 'rules' are those suggested by Soup and me. Just be aware that you may encounter sentences, such as #1 which do not follow the rules. Don't worry - #2 is acceptable.
Oh my God!
I am a disaster!![]()
No, you are not. Your 'Could you tell me which the correct form is?' was correct and natural. The sentence that Soup correctly put aby was incorrect because there was no 'the' in front of 'correct' .
If you found my last post confusing, ignore it. I wrote that only because some learners become unhappy when they hear a native speaker saying something that they (the learners) believe to be incorrect.