For people with vision impairments, please make the distinction between a selected button and an unselected button more obvious. In the screenshots I provided below, you will see that, in the one where "agree" is selected, the difference in color is nearly indistinguishable.

I experimented with various settings and color schemes but all operated in the same way, with the color of a selected response nearly indistinguishable from the remaining, unselected buttons.