@Ronel: Best option is to copy the whole css from parent theme responsive.css and then add your custom below. As the code I gave you will remove the parent theme responsive.css and then add your child theme responsive.css
But if you want to create new responsive.css in your child theme with only few css that you want to edit. Then you don’t need to remove parent theme css. You just need to add your child theme responsive.css by adding in the following code in your child theme functions.php file.
// dding new responsive.css in child theme
function adventurous_child_enqueue_scripts() {
wp_enqueue_style( 'adventurous-child-responsive', get_stylesheet_directory_uri() . '/responsive.css' );
}
add_action( 'wp_enqueue_scripts', 'adventurous_child_enqueue_scripts', 11 );