English Grammar find the error in given sentence

they has come upon /(a)a business that will make /(b)them a lot of money./(c) no - they has come upon / (a) a business that will make / (b) them a lot of money./(c) no - find the error in given sentence English Grammar in hindi,  Spot the error  question answers in hindi pdf   questions in hindi, Know About English Grammar online test English Grammar notes in hindi quiz book