The correct option is D Amritesh
Arun's score = 495
Arjit's score = 531
Amritesh's score = 558
Amit's score = 431 + t, where t is his score in test 3 which can take the maximum value of 100, so his maximum overall score can be 531
Ankur's score = 501 + x, but it's already given that Ankur is not the topper.
Hence among these students, Amritesh's score is highest and he is the topper.