CREATE TABLE table_name_15 (country VARCHAR, date VARCHAR, company VARCHAR)

For the Enernoc Australia Pty Ltd, what's the country with an unknown date?
SELECT country FROM table_name_15 WHERE date = "unknown" AND company = "enernoc australia pty ltd"
SELECT "country" FROM "table_name_15" WHERE "company" = "enernoc australia pty ltd" AND "date" = "unknown"