How to set old value for SELECT tag in Laravel

create.blade.php

<select  id="category" class="form-control" name="category"  required>
<option selected disabled>- Select -</option>
<option  value="">
<option value="A">A</option>
<option value="B">B</option>
<option value="C">C</option>
</select>

Error : Undefined variable: key (View: C:\xampp\htdocs\LaravelCrud_x\resources\views\create.blade.php)

via Chebli Mohamed