Even Though Each Item on the Distance Ladder Is Only

Multiple Choice

Even though each item on the distance ladder is only effective within a certain distance range, the concept is still effective because

A) each technique produces exact distances on its own.
B) the distance ladder concept can be verified by looking in different wavelength ranges.
C) each step can be calibrated through its overlap with the previous step.
D) distances are ultimately relative, and not absolute.
E) the time delay due to light travel time is significant enough to limit the accuracy of distance measurements anyway.