Unable to hide message for correct or incorrect answer

Screenshot tells me that you are using version 12. You cannot set this up globally... as was possible with the quizzing master slides in all previous versions of Captivate. Moreover the feedback messages are not individual captions, but they are states in a multistate object where the Default state is empty. You cannot just get rid of one of the states.

A while ago I proposed a clumsy workaround. Go to the Default Labels under Quiz Preferences and delete the texts you don't want to appear. Show the 'Caption' in the Components, and edit the colors of the states: make them completely transparent and set the border width to 0px.  Too bad I couldn't find how to change the timing for the appearance of the messages. All those settings were so easy to change in all older versions, why do they complicate it so much in this new version that was meant to be 'intuitive'?