Is there a way for select dropdown field to default to empty basically a placeholder?

[hramli-redventures]

Given the following

            Field::make('select', 'crb_select_field', 'Select Number')
                ->set_required(true)
                ->set_options( array(
                    '1' => 1,
                    '2' => 2,
                    '3' => 3,
                    '4' => 4,
                    '5' => 5,
                ))

the way it is, this will default to '1', but I would like it to default to a placeholder "please select a number" or something like that.

Same issue with radio box, is there a way to default to not selected?