There are some black lines in the absorption spectrum. Can you figure out what these are?

a$)$ The gas cloud acts as a "smokescreen" and diffuses light of specific wavelengths

b$)$ The gas cloud acts as a "mirror" and reflects light of specific wavelengths

c$)$ The gas cloud acts as a "filter" and absorbs light of specific wavelengths

d$)$ The gas cloud acts as a "crystal" and diffracts light of specific wavelengths