<script src="http://code.jquery.com/jquery-1.10.2.min.js" type="text/javascript"></script>
<script language="javascript" type="text/javascript">
/**
if F01-a is No
    then F01-b , F01-c & F01-d either don’t show or are forced to N/A
only if question F01-b is No
    then F01-c & F01-d don’t show or are forced to N/A
only if question F01-c is No then F01-d don’t show or is forced to N/A only
**/
$(document).ready(function(){
    $("select[title^='F01'").change(function(){
        var title = $(this).attr("title");
        var selected = $(this).find("option:selected").text();
        if(title == "F01-a" && selected == "No") {
            //set F01-b , F01-c & F01-d to N/A
            $("select[title='F01-b']").val("N/A");
            $("select[title='F01-c']").val("N/A");
            $("select[title='F01-d']").val("N/A");
            //hide F01-b , F01-c & F01-d
            $("select[title='F01-b']").hide();
            $("select[title='F01-c']").hide();
            $("select[title='F01-d']").hide();
            // or set F01-b , F01-c & F01-d read-only
            //$("select[title='F01-b']").prop("disabled", "disabled");
            //$("select[title='F01-c']").prop("disabled", "disabled");
            //$("select[title='F01-d']").prop("disabled", "disabled");
        }else if (title == "F01-b" && selected == "No"){
            //set F01-c & F01-d to N/A
            $("select[title='F01-c']").val("N/A");
            $("select[title='F01-d']").val("N/A");
            //hide F01-c & F01-d
            $("select[title='F01-c']").hide();
            $("select[title='F01-d']").hide();
            // or set F01-c & F01-d read-only
            //$("select[title='F01-c']").prop("disabled", "disabled");
            //$("select[title='F01-d']").prop("disabled", "disabled");
        }else if (title == "F01-c" && selected == "No"){
            //set F01-d to N/A
            $("select[title='F01-d']").val("N/A");
            //hide F01-d
            $("select[title='F01-d']").hide();
            // or set F01-d read-only
            //$("select[title='F01-d']").prop("disabled", "disabled");
        }else{
            //enable F01-b F01-c & F01-d
            $("select[title='F01-b']").show()
            $("select[title='F01-c']").show();
            $("select[title='F01-d']").show();
            //$("select[title='F01-b']").prop("disabled", "");
            //$("select[title='F01-c']").prop("disabled", "");
            //$("select[title='F01-d']").prop("disabled", "");
        }
    });
});
</script>