When 6 of the integers from 1 to 9 are placed in the boxes below such that each box contains a different number, all equalities are satisfied.
$$\begin{aligned}
& \square + \square = 5 \\
& \square - \square = 5 \\
& \square : \square = 5
\end{aligned}$$
Accordingly, what is the sum of the unused integers?\\
A) 23\\
B) 21\\
C) 19\\
D) 17\\
E) 15