CREATE TABLE table_6554 ("Task No." FLOAT, "Day announced" TEXT, "Options" TEXT, "Viewers' selection" TEXT, "Result" TEXT)

What were the options that were completed before the 4 th task that had viewers selecting nan?
SELECT "Options" FROM table_6554 WHERE "Result" = 'completed' AND "Task No." < '4' AND "Viewers' selection" = 'nan'
SELECT "Options" FROM "table_6554" WHERE "Result" = 'completed' AND "Task No." < '4' AND "Viewers' selection" = 'nan'