dropdown not show value

i have added dropdown simple booststrap but didn't show value in dropdown

<div class="form-group">
    <label class="control-label">Category @include('required-symbol')</label>
    <select class="form-control"  title="category" name="category" id="categories" data-placeholder="Please select a user role" data-allow-clear="true" style="min-width: 100%">
        <option value="A">A</option>
        <option value="A">A</option>
        <option value="A">A</option>
    </select>
</div>

via Chebli Mohamed