add custom option to get_categories dropdown

Question

I have a dropdown menu for selecting categories in a widget that I am working on. Everything is working and options are being saved in the database. What I am trying to do now is add a blank option instead of it being automatically set when you click save. In this situation, the user might not want to set a category.

  $this->categories = get_categories();
            foreach ( $this->categories as $cat ) {
                $selected = ( $cat->term_id == esc_attr( $category ) ) ? ' selected = "selected" ' : '';
                $option = '<option '.$selected .'value="' . $cat->term_id;
                $option = $option .'">';
                $option = $option .$cat->name;
                $option = $option .'</option>';
                echo $option;
            }

How can I append a blank option to the select?

Answer 1

I presume there is an open option html element before that code provided. After that select tag is opened and before you run through that loop echo out a blank option with value=""