radiobutton list format in bootstrap?

hi,
within bootstrap  I have RadioButtonList below - it looks fine on computer and tablets but on mobile
the format is lost as items are crushed  together.
instead of repeat column=2 is it possible to make it 1 column for mobile so that the format remains clear??

        <div class="form-group">       <label for="pwd">Occasion:</label>          <asp:RadioButtonList ID="RadioButtonList3" runat="server" class="radio"                                                  RepeatColumns="2"  Ce ...