It can be inferred from the sentence highlighted in the passage that a standard candle is useful to scientists for which of the following reasons? A. Standard cartdles do not have their own locus of motion. B. Standard candles more reliably adhere to the law of inverse squares than do other supernovas. C. Only standard candles provide a known measure of brightness. D. Knowledge of an object's brightness allows scientists to measure the speed at which the object is moving toward Earth. E. Knowledge of an object's brightness allows scientists to accurately measure its distance from Earth.