Hey
@rhonaf! An answer choice is always going to change to a different background color when selected! Without using custom code, I would recommend a few changes that you can make from within the platform:
1. Change your theme to one where the selected answer choice color is a bit more subtle or neutral.
2. Edit the images so that a background color is already added. In your second image for example, the 'Excellent' answer choice option already has this white background added.
3. It looks like the answer choice may be a part of your image, instead you can remove it from the image and edit the answer choice text to a lighter color.