You have some syntax errors in your script and are targeting the wrong element. Additionally, you will need to hide the pseudo-elements (fake checkboxes) inserted by LimeSurvey.
I would add something like this to the question source:
Code:
<script charset="utf-8" type="text/javascript">
$(document).ready(function() {
$( '#question{QID} .question-item:eq(0)').addClass('hide-pseudo-elements').find('input.checkbox').remove();
});
</script>
And, add something like this to the end of
template.css:
Code:
.hide-pseudo-elements label::before,
.hide-pseudo-elements label::after {
display: none;
}
.hide-pseudo-elements .label-text {
margin-left: -20px;
}
I would do the same thing for your second "headline" (see my attached version of your survey). As you have that now, simply adding text in the label for "C", if you click on that "headline", the "C" checkbox will be toggled.
Survey attached:
