DropDown Custom Field With If Else that show off options

Hello guys i have a trouble!

i would like to ask you how can i make 1 condition code for each option of the bellow function field_cliente :

function field_cliente( $fields) {
    $fields['billing']['billing_cliente'] = array (
        'label' => __('Tipo di Cliente', 'woocommerce'),
        'id' => '_select', 
        'type' => 'select',
        'options' => array (
            'default' => __( 'Seleziona', 'woocommerce' ),
            'one' => __( 'Privato', 'woocommerce' ),
            'two' => __( 'Azienda', 'woocommerce' ),
            'three' => __( 'Impresa Individuale', 'woocommerce' )
        )
    );

    return $fields;
}

For example:

If "One" {
    add_filter(' ..');
    etc...
}

if "Two" {
    add_filter(' ..');
}

I need to know the way of do it because i’m trying to make a show off of filters for each condition choose by the client in the web page checkout