what is the class when the power is 22500 watts?
CREATE TABLE "s_rebroadcaster_of_cjbc" (
  "city_of_license" text,
  "identifier" text,
  "frequency" text,
  "power" text,
  "class" text,
  "rec_net" text
);
SELECT "class" FROM "s_rebroadcaster_of_cjbc" WHERE "power"='22500 watts';