JSFiddle - React, Tailwind, and code Playground
HTML
<label for="cell">3. Do you currently have a cell phone? (Y/N)</label>
<input type="checkbox" name="cell" id="cell" data-on="Yes" data-off="No" />
<div class="hide_if_no" style="display: none;">
<label for="blackBerry">4. If YES, is the cell phone a BlackBerry? (Y/N)</label>
<input type="checkbox" name="blackBerry" id="blackBerry" data-on="Yes" data-off="No" />
</div>
JavaScript
$('#cell').click(function() {
$('.hide_if_no').toggle(this.checked);
});