Let $A$ and $B$ be two sets such that $A \cup B = \{1,2,3,4,5,6,7,8,9\}$ and
- the sum of two elements from the set $A \setminus B$ is 8,
- the difference of two elements from the set $A \cap B$ is 8,
- the product of two elements from the set $B \setminus A$ is 8.
If the sum of elements in set $A$ equals the sum of elements in set $B$, what is the sum of elements in $A \cap B$?
A) 10
B) 17
C) 18
D) 23
E) 25