Let $A$, $B$, $C$ and $D$ be digits;
\begin{itemize}
\item the four-digit number $ABCD$ is divisible by 20,
\item the three-digit number $ADB$ is divisible by 18,
\item the three-digit number $CDA$ is divisible by 15.
\end{itemize}
Accordingly, what is the sum $A + B + C + D$?
A) 10
B) 11
C) 12
D) 13
E) 15