CREATE TABLE table_2290 ("No. in series" FLOAT, "No. in season" FLOAT, "Title" TEXT, "Directedby" TEXT, "Writtenby" TEXT, "Originalairdate" TEXT, "Production code" TEXT, "U.S. viewers  ( million ) " TEXT)

Who directed the episode with a production code of 4WAB05?
SELECT "Directedby" FROM table_2290 WHERE "Production code" = '4WAB05'
SELECT "Directedby" FROM "table_2290" WHERE "Production code" = '4WAB05'