SONIC recognized franchisees and operators at the 2017 SONIC National Convention   Gary Kinslow, SONIC Franchisee, wins the restaurant chain's most prestigious award OKLAHOMA CITY, 2017-Oct-10 — /EPR Retail News/ — SONIC® Drive-In (NASDAQ: SONC), the nation's largest chain of drive-in restaurants, presented ten awards to franchisees and operators at the 2017 SONIC National Convention in Denver, Colo. Every year, SONIC recognizes exemplary individuals…