What was the maximum average of the episode with a Chinese title 古靈精探b?
CREATE TABLE "highest_rating_drama_series_of_2009" (
  "rank" real,
  "english_title" text,
  "chinese_title" text,
  "average" real,
  "peak" real,
  "premiere" real,
  "finale" real,
  "hk_viewers" text
);
SELECT MAX("average") FROM "highest_rating_drama_series_of_2009" WHERE "chinese_title"='古靈精探B';