Which League Cup has a FA Cup of 5, and a Club of boston united, and a League smaller than 16?
CREATE TABLE "top_scorers_in_order_of_league_goals" (
  "player" text,
  "club" text,
  "league" real,
  "fa_cup" real,
  "fa_trophy" real,
  "league_cup" real,
  "total" real
);
SELECT MAX("league_cup") FROM "top_scorers_in_order_of_league_goals" WHERE "fa_cup"=5 AND "club"='boston united' AND "league"<16;