CREATE TABLE table_31708 ("Call sign" TEXT, "Frequency MHz" FLOAT, "City of license" TEXT, "ERP W" TEXT, "Class" TEXT, "FCC info" TEXT)

Name the city of license for call sign of k215es
SELECT "City of license" FROM table_31708 WHERE "Call sign" = 'k215es'
SELECT "City of license" FROM "table_31708" WHERE "Call sign" = 'k215es'