Use the given real number line to compute each distance.
$$
\begin{array}{cccccccc}{A} & {B} & {C} & {D} & {E} & {} & {} & {} \\ {} & {A} & {B} & {C} & {1} & {1} & {1} & {1} & {1} \\ \hline-4-3 & {-2} & {-1} & {0} & {1} & {2} & {3} & {4} & {5} & {6}\end{array}
$$
$$
d(C, D)
$$