You can use something like this:
// Hide option number 2 from the top (list is 0-indexed)
jQuery("#dffs_ChoiceColumn2").find(".ms-RadioText:eq(1)").hide();
// Show option number 2 from the top (list is 0-indexed)
jQuery("#dffs_ChoiceColumn2").find(".ms-RadioText:eq(1)").show();
Replace “ChoiceColumn2” with your fields internal name.
Hope this gets you on track,
Alexander