The sentence ends by using a string of "wh-" noun clauses. These clauses will not be questions, so the last a person should also not be a matter. "Which 1 could be the best" is clearly a matter structure, so it is sensible that " Of specific issue is that https://share.evernote.com/note/8017dd9b-bae1-b7b2-e7a5-981f51e2ee16