If Hydrogen Is the Most Common Element in the Universe

Multiple Choice

If hydrogen is the most common element in the universe, why do we not see the lines of hydrogen in the spectra of the hottest stars?

A) in the hottest stars, hydrogen nuclei are forced to break apart into smaller nuclei
B) in the hottest stars, all hydrogen in the star has quickly fused into helium
C) in the hottest stars, hydrogen can quickly combine with oxygen to make H₂O, whose spectrum consists of completely different lines
D) in the hottest stars, the hydrogen atoms experience a huge Doppler shift, which moves the lines in the spectrum to a completely unrecognizable place
E) in the hottest stars, hydrogen atoms are ionized, and so there are no electrons to produce lines in the spectrum