If I have a question for a special member of OC, then can I able to tag that member in my question? you may consider it as ” asking a question from one member only “
This is not a feature on OC. So, you cannot. Btw why would anyone want to do that? Questions asked on OC are general questions. They are answered by all members.
If you have good reason for this option, you can submitted directly your idea to admin.