diff --git a/exercises/concept/authentication-system/AuthenticationSystem.cs b/exercises/concept/authentication-system/AuthenticationSystem.cs
index fa35c435e3..3a02d7e3f1 100644
--- a/exercises/concept/authentication-system/AuthenticationSystem.cs
+++ b/exercises/concept/authentication-system/AuthenticationSystem.cs
@@ -8,7 +8,7 @@ private class EyeColor
         public string Green = "green";
         public string Brown = "brown";
         public string Hazel = "hazel";
-        public string Brey = "grey";
+        public string Grey = "grey";
     }
 
     public Authenticator(Identity admin)