Without any third party assets except playmaker it will be a very hard task. Answering requires the computer to understand the user input. You could do this by searching for certain keywords ("String contains" , Regex etc.) , but you could never rule out the possibility that the user answers not as you expect (e.g "yep" instead of "yes" ) or generally avoid typos. Understanding language would require a complex system featuring some sort of machine learning or cloud databases.
Thats why you often see prewritten dialog options inside games like Skyrim - it can be tied to a state, the story will progress as you want it and the user cant fall flat because he uses some kind of slang or misspelling.
EDIT : You might want to look at the game SUPERHOT - it has a very cool way to display dialogue - the user has to enter an answer, but no matter which buttons he presses the correct answer/question writes out on display. It is a very creative approach to the problem