Sets A and B, shown in the Venn diagram, have the same number of elements. Their union has 2007 elements and their intersection has 1001 elements. Find the number of elements in A.

Answer Choices
A. 503
B. 1006
C. 1504
D. 1507
E. 1510
Sets A and B, shown in the Venn diagram, have the same number of elements. Their union has 2007 elements and their intersection has 1001 elements. Find the number of elements in A.

Answer Choices
A. 503
B. 1006
C. 1504
D. 1507
E. 1510