CREATE TABLE table_79789 ("Call sign" TEXT, "Frequency" TEXT, "City of license" TEXT, "Facility ID" FLOAT, "ERP / Power W" FLOAT, "Height m  (  ft  ) " TEXT, "Class" TEXT, "FCC info" TEXT)

What city has the A Class licence?
SELECT "City of license" FROM table_79789 WHERE "Class" = 'a'
SELECT "City of license" FROM "table_79789" WHERE "Class" = 'a'