WordPress at a glance
function is not described

delete_blog_option() WP 3.0.0

Removes option by name for a given blog id. Prevents removal of protected WordPress options.

No Hooks.

Return

true/false. True, if option is successfully deleted. False on failure.

Usage

delete_blog_option( $id, $option );
$id(int) (required)
A blog ID. Can be null to refer to the current blog.
$option(string) (required)
Name of option to remove. Expected to not be SQL-escaped.

Code of delete blog option: wp-includes/ms-blogs.php WP 5.2.1

<?php
function delete_blog_option( $id, $option ) {
	$id = (int) $id;

	if ( empty( $id ) ) {
		$id = get_current_blog_id();
	}

	if ( get_current_blog_id() == $id ) {
		return delete_option( $option );
	}

	switch_to_blog( $id );
	$return = delete_option( $option );
	restore_current_blog();

	return $return;
}