possible to exclude levels and change how questions are served

lib/src/widgets/options_grid.dart

@@ -41,15 +41,13 @@ class OptionsGrid extends StatelessWidget {
         if (showResult) {
           if (correctAnswers != null && correctAnswers!.contains(o)) {
             currentButtonColor = theme.colorScheme.tertiary;
-          } else if (o == selectedOption) {
-            currentButtonColor = theme.colorScheme.error;
           }
         }
 
         return SizedBox(
           width: 160,
           child: ElevatedButton(
-            onPressed: isDisabled ? null : () => onSelected(o),
+            onPressed: isDisabled || o == '---' ? null : () => onSelected(o),
             style: ElevatedButton.styleFrom(
               backgroundColor: currentButtonColor,
               foregroundColor: currentTextColor,