<label for="dropdownMenu" style="display: block; line-height: 150%; padding: 1px 0pt 3px; white-space: nowrap" >Preferred Language</label>
<select id="field8" name="dropdownMenu" style="width: 100%" >
<option value="First" >English</option>
<option value="Second" >French</option>
<option value="Third" >Ducht</option>
<option value="Third" >German</option>

</select>

<script>
select = document.getElementById('field8')
options = select.getElementsByTagName('option')
for (var i = 1; i < options.length; i++) {
    if(options[i].innerHTML == 'French')
        continue;
    options[i].style.display = 'none'
}
</script>