Tengo un formulario con un campo desplegable en PHP con esta matriz:

$field["options"] = array(
     array("value" => "Chişinău", "text" => "Chişinău", "depth" => 0),
     array("value" => "Bălţi", "text" => "Bălţi", "depth" => 0),
     array("value" => "Comrat", "text" => "Comrat", "depth" => 0),
     ...
     array("value" => "Ungheni", "text" => "Ungheni", "depth" => 0)
);

Cómo agregar como primera opción el<option selected disabled>Choose one</option>?