A graphical display of accumulated costs and labor hours for both budgeted and actual costs, plotted against time, is called ?

The answer is a progress S-curve.

S Curve :

A graphical display of accumulated costs and labor hours for both budgeted and actual costs, plotted against time

It is S curve which present all situation of project progress with respect to project cost.

That would be a control chart used for monitoring a process performance and thus for identifying the variations. 

E. S curve. --------------------