Absorption Lines Due to Interstellar Gas

Multiple Choice

Absorption lines due to interstellar gas

A) are wider than the lines from stars because the gas is hotter than most stars.
B) are more narrow than the lines from stars because the gas has a lower pressure than stars.
C) indicate that the interstellar medium contains dust.
D) indicate that the interstellar medium is expanding away from the sun.
E) none of the above.