How do i use those tricky IF statements for options

im looking for a way for my program to check for the users input. Its either option A or option B. If they input "A" or "B" then blah blah blah. how can i check if they input those certain characters which were given to them as options.

basically what im trying to do is something like

Do you, Go into the forest (A) or go to the house (B)

program checks for inputs such as A or B