Answer
The Serbian Cyrillic spelling of Gojko Kačar's surname is Качар. This spelling is based on the Serbian pronunciation of the name, which is "Kachar." The "K" sound is represented by the Cyrillic letter "К," the "A" sound is represented by the Cyrillic letter "А," the "Ч" sound is represented by the Cyrillic letter "Ч," and the "Р" sound is represented by the Cyrillic letter "Р."