min score is 500 and max is 750
Person 1, range is 50, minimum score can be 500 to 700 and max score can be 550 to 750
Person 2, range is 80, minimum score can be 500 to 670 and max score can be 580 to 750
Person 3, range is 120, minimum score can be 500 to 630 and max score can be 620 to 750
possible maximum range of scores could be when person 3 has max score of 750 and person 1 max score is 550 = 200
possible minimum in the above case is 630-500=130
difference = 70
B