A rectangular grid of squares has 141 rows and 91 columns. Each square has room for two numbers. Horace and Vera each fill in the grid with the numbers 1 through 141\times 91=12{,}831. Horace fills horizontally (left to right within each row); Vera fills vertically (top to bottom within each column). How many squares get two copies of the same number?
Answer Choices:
A. 7
B. 10
C. 11
D. 12
E. 19