Final answer:
The 'Dirty Ice' found in interstellar dust is similar to the composition of comets, which contain frozen volatile materials and solid grains. (option a)
Step-by-step explanation:
The 'Dirty Ice' interstellar dust has a composition similar to that of comets, which are small icy objects containing frozen water and other volatile materials mixed with solid grains. Comets are known for their icy make-up, consisting of frozen gases such as water, carbon dioxide, and carbon monoxide, and form in the cooler regions of the solar system, far beyond Neptune's orbit.
They are remnants of the solar system's formation and remain largely unchanged since that time. When comets approach the Sun, their ices evaporate and release rock and dust, contributing to the interstellar dust found in the inner solar system.
Hence, the answer is option a