AMC 8 1996 Problem 8

Points $A$ and $B$ are 10 units apart. Points $B$ and $C$ are 4 units apart. Points $C$ and $D$ are 3 units apart. If $A$ and $D$ are as close as possible, then the number of units between them is $\text{(A)}\ 0 \text{(B)}\ 3 \text{(C)}\ 9 \text{(D)}\ 11 \text{(E)}\ 17$