In the diagram, the grid has 150 rows and 150 columns, numbered from 1 to 150. In row 1, every box is shaded. In row 2, every second box is shaded. In row 3, every third box is shaded. The shading continues in this way, so that every nth box in row n is shaded. Which column has the greatest number of shaded boxes?
Answer Choices
A. 144
B. 120
C. 150
D. 96
E. 100