Edit in JSFiddle

$(function () {
    $('#yes').click(function (event) {
        if (event.target.checked) {
            $('#no').find('input').removeAttr('checked');
        }
    });
    $('#no').click(function (event) {
        if (event.target.checked) {
            $('#yes').find('input').removeAttr('checked');
        }
    });
});

<fieldset>
    <legend>Yes</legend>
    <div id="yes">
        <input type="checkbox" id="a" />
        <label for="a">Yes, A</label>
        <br/>
        <input type="checkbox" id="b" />
        <label for="b">Yes, B</label>
        <br/>
    </div>
</fieldset>
<fieldset>
    <legend>No</legend>
    <div id="no">
        <input type="checkbox" id="c" />
        <label for="c">No, C</label>
        <br/>
        <input type="checkbox" id="d" />
        <label for="d">No, D</label>
        <br/>
    </div>
</fieldset>





<!-- Post Info -->
<div style='position:fixed;bottom:0;left:0;    
            background:lightgray;width:100%;'>
    Blogged About: <a href='http://codingeverything.blogspot.com/2013/02/mutually-exclusive-checkboxes-with.html'>Mutually Exclusive Checkboxes with JQuery</a><br/>
    Find documentation: <a href='http://api.jquery.com/removeAttr/'>jQuery .removeAttr()</a><br/>
    Find documentation: <a href='http://api.jquery.com/event.target/'>jQuery event.target</a>
<div>