What is the chassis of rahel frey's volkswagen engine?
CREATE TABLE "teams_and_drivers" (
  "team" text,
  "driver" text,
  "class" text,
  "chassis" text,
  "engine" text,
  "rounds" text
);
SELECT "chassis" FROM "teams_and_drivers" WHERE "engine"='volkswagen' AND "driver"='rahel frey';