Well done Dawn. So far you are only one with the answer. My compliments to your son who helped you.
Easy hint for others - The building shown in the quiz is a monarch's residence.
Similarly all other photos/images from various other sources are under the copyright of their respective owners, web portals/application etc from which these were obtained. Wherever possible due acknowledgement has been made about the source.
Actual terms of copyright/reuse is available in the source link given below each image.