Defines how labels are displayed. Depending on what component wraps it, <apex:chartLabel>
gives you options for affecting labels for bar and line series labels, pie chart segments, and axes
labels.
Note: This component must be enclosed by a data series component (<apex:barSeries>,
<apex:lineSeries>, or <apex:pieSeries>) or an <apex:axis> component.

A.
apex:chart

B.
apex:include

C.
apex:chartLabel

D.
apex:messages