Duolingo gives you select choices not free text for this question and Omar is not there to pick only David and Tamer, meaning everyone will by default answer this one wrong.
Not sure who gave me a down vote. Don't think you understand the fault I'm reporting.
It was not possible to type the answer when this question came and the only 2 names available to pick in the bubbles were NOT Omar. So it was impossible to answer this question correctly.