After a Lot of Work, a Group of Graduate Students

Multiple Choice

After a lot of work, a group of graduate students has finally measured the wavelengths of many dozens of lines in the spectrum of a distant star. If a number of the lines come from molecules such as titanium oxide, the star is likely to be which spectral type:

A) O
B) B
C) A
D) M
E) we need more information; lines from molecules can be found in stars of every spectral type