         if let choice = answerDTO.choice{
             if let choiceIndex = questionDTO.choices.indexOf({$0 === choice}){
                 buttons[choiceIndex].selected = true
-                buttons[choiceIndex].layer.backgroundColor = Colors.grades[questionDTO.choices[choiceIndex].grade].CGColor
+                buttons[choiceIndex].layer.backgroundColor = Colors.grades[abs(questionDTO.choices[choiceIndex].grade)].CGColor
             }
         }
         

            if let button = self.view.viewWithTag(20 + i) as? UIButton{
                button.setTitle(questionDTO.choices[i].choiceText, forState: .Normal)
                button.layer.cornerRadius = 5
                button.layer.backgroundColor = Colors.gradesLight[questionDTO.choices[i].grade].CGColor
                buttons.append(button)
            }
        }

            if button == sender && !button.selected{
                button.selected = true
                if let btnIndex = buttons.indexOf(button){
                    button.layer.backgroundColor = Colors.grades[abs(questionDTO.choices[btnIndex].grade)].CGColor
                    answerDTO.choice = questionDTO.choices[btnIndex]
                    print("Choice: \(answerDTO.choice!.choiceText)")
                }
            } else {
                button.selected = false
                if let btnIndex = buttons.indexOf(button){
                    button.layer.backgroundColor = Colors.gradesLight[abs(questionDTO.choices[btnIndex].grade)].CGColor
                }
                if button == sender{
                    answerDTO.choice = nil
