Darren is a certified interior designer with a lucrative client list in the city of​ kelsa, situated in the state of touslon. his business affords him a substantial amount of goodwill from his clients. darren sells his accounting interior designing business to glenda. when he sells his business to​ glenda, darren agrees not to open another interior designing firm in the city of kelsa for a​ 25-year period. what kind of agreement exists between darren and glenda in this​ case?