Answer:
c. $_SERVER
Step-by-step explanation:
$_SERVER is an array in PHP containing information about headers, paths, and script locations.
Example usage:
echo $_SERVER['HTTP_HOST'];
This will print information about HTTP_HOST header.
echo $_SERVER['DOCUMENT_ROOT'];
This provides information about document root path.
echo $_SERVER['SCRIPT_FILENAME'];
This provides information about the currently executing script.