Answer:
(b) gas and dust
Step-by-step explanation:
"The interstellar medium is the stuff between the stars. Made up mostly of hydrogen and helium gas – plus trace amounts of ices, silicate grains, and all the other elements – it contains all the material needed to make stars and planets. It is shaped by stellar winds, dying stars, galactic magnetic fields, and supernova explosions."
"The interstellar medium is filled primarily with hydrogen gas. A relatively significant amount of helium has also been detected, along with smaller percentages of such substances as calcium, sodium, water, ammonia, and formaldehyde . Sizable quantities of dust particles of uncertain composition are present as well."