Currently in the Destiny's Tutor Quest, hovering over the correct answer says "Druss Blade" whereas hovering over the wrong answers doesn't show anything. So it is no challenge even on first try. My guess is that all riddle "choose the correct answer" dialogs that provide an item show up when hovering over the correct answer. If this is so, can you provide an option to hide item rewards for choice dialogs? Or even better, have an option to hide or show for ALL possible reward types, so that you can choose for all rewards to be hidden for that particular dialog "page" or all rewards to be shown for that particular dialog page (including items, resources, troops, champions, monsters etc.).
EDIT: I'm not sure if the Nimbly quests/events show the item received from a correct choice. If they don't, then I wonder why the Destiny's Tutor quest does for the right choice? If the Nimbly reward (Dagger of the Leech for example) DOES show up when for the correct choice, then it is a global issue for riddle based quest dialogs that give an item for the right choice.