CREATE TABLE table_4172 ("Series #" FLOAT, "Production Code" FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "United States Original Airdate" TEXT, "Canada Original Airdate" TEXT)

What is the original United States air date of the episode written by Mike Ferris?
SELECT "United States Original Airdate" FROM table_4172 WHERE "Written by" = 'Mike Ferris'
SELECT "United States Original Airdate" FROM "table_4172" WHERE "Written by" = 'Mike Ferris'