override function jnews_get_primary_category

function jnews_get_primary_category( $post_id ) {
    $category_id = null;

    if ( get_post_type( $post_id ) === 'post' ) {
        $category = vp_metabox( 'jnews_primary_category.id', null, $post_id );

        if ( ! empty( $category ) ) {
            $category_id = $category;
        } else {
            $categories         = get_the_category( $post_id );
            $primary_categories = array();
            $exclude_categories = array( 30, 31, 2, 29 ,4 ); /*  change this value with all categories id you want exclude from primary category*/
            foreach ( $categories as $key => $category ) {
                if ( ! in_array( $category->cat_ID, $exclude_categories ) ) {
                    array_push( $primary_categories, $category );
                }
            }
            $categories = ( ! empty( $primary_categories ) ) ? $primary_categories : $categories;
            $categories = array_slice( $categories, 0, 1 );
            if ( empty( $categories ) ) {
                return null;
            }
            $category    = array_shift( $categories );
            $category_id = $category->term_id;
        }
    }
    return apply_filters( 'jnews_primary_category', $category_id, $post_id );
}