A router can reach four different organizations via the same interface. The IP prefixes used by the different organizations are $108.25.224.0/21, 108.25.232.0/21, 108.25.240.0/21$ and $108.25.248.0/21 $. What $\textbf{IP}$ prefix can the router aggregate the prefixes to? Express in the form $A.B.C.D/X$ (e.g., $108.25.248.0/16)$. Note the bit pattern corresponding to $224$ is $11100000, 232 \text{ is } 11101000, 240 \text{ is } 11110000 \text{ and } 248 \text{ is } 11111000.$