For the Enernoc Australia Pty Ltd, what's the country with an unknown date?
CREATE TABLE "list_of_subsidiaries" (
  "date" text,
  "company" text,
  "business" text,
  "country" text,
  "value_usd" text
);
SELECT "country" FROM "list_of_subsidiaries" WHERE "date"='unknown' AND "company"='enernoc australia pty ltd';