Studying a Spectrum from a Star Can Tell Us a Lot

Studying a spectrum from a star can tell us a lot. All of the following statements are true except one. Which statement is not true?

A) The total amount of light in the spectrum tells us the star's radius.
B) We can identify chemical elements present in the star by recognizing patterns of spectral lines that correspond to particular chemicals.
C) The peak of the star's thermal emission tells us its temperature: hotter stars peak at shorter (bluer) wavelengths.
D) Shifts in the wavelengths of spectral lines compared to the wavelengths of those same lines measured in a laboratory on Earth can tell us the star's speed toward or away from us.