If the sum of the first 3n positive integers is 150 more than the sum of the first n positive integers, then the sum of the first 4n positive integers is<spanclass=′latex−bold′>(A)</span>300<spanclass=′latex−bold′>(B)</span>350<spanclass=′latex−bold′>(C)</span>400<spanclass=′latex−bold′>(D)</span>450<spanclass=′latex−bold′>(E)</span>600