GAUSS7 2012 Problem 25

The positive integers are arranged in rows and columns as shown below.

Image

More rows continue to list the positive integers in order, with each new row containing one more integer than the previous row. How many integers less than 2000 are in the column that contains the number 2000?

Answer Choices
A. 15
B. 19
C. 17
D. 16
E. 18