The correct option is C iii, ii, iv, v
Here, the most coherent sequence is [iii- ii- iv- v]: The release of atomic energy is the greatest achievement which science has attained [i]. The atom was split by physicists whose minds were set on the search for knowledge [iii]. But the first invention to which their discoveries were applied was a bomb [ii]. It was more deadly than any other weapon invented so far [iv]. It is with dread that scientists regard the first use to which their greatest discovery was put [v]. However, they are gratified by the numerous applications of atomic energy for peaceful and constructive population [vi]. So, option C is the answer.