A sequence of natural numbers is constructed by listing the first 4 , then skipping one, listing the next 5 , skipping 2 , listing 6 , skipping 3 , and, on the $n$th iteration, listing n+3 and skipping n. The sequence begins 1,2,3,4,6,7,8,9,10,13. What is the 500,000 th number in the sequence?

**Answer Choices**

A. 996506

B. 996,507

C. 996,508

D. 996,509

E. 996,510