eskize,
<!DOCTYPE HTML>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.11.0/jquery.min.js"></script>
<script>
$(function ()
{
$('.answers').click(function ()
{
var b = $(':checked');
b.parent().css({background: 'rgba(0, 204, 51, 1)'})
}
)
}
)
</script>
</head>
<body>
<div class='answers'>
<label><input type='radio' name='answer'> Текст</label>
<label><input type='radio' name='answer'> Текст</label>
<label><input type='radio' name='answer'> Текст</label>
</div>
</body>
</html>