What is Halley's Comet largely composed of?

Halley's Comet is primarily composed of ices and rocky materials, which is characteristic of comets in general. This composition includes water ice, frozen gases, such as carbon dioxide, carbon monoxide, and ammonia, as well as dust and small rocky particles. When a comet approaches the Sun, the heat causes these ices to sublimate, releasing gas and dust and forming the distinctive coma and tail characteristic of comets. This combination of ices and rocky materials allows Halley's Comet to reflect its behavior and appearance as it orbits the Sun approximately every 76 years.

In contrast, other compositions mentioned do not accurately represent what constitutes Halley's Comet. For instance, a composition of only metals would not reflect its observed properties, and gas and liquid alone do not account for the solid structure found within comets. Similarly, metal and dust do not encompass the significant amount of ices that are crucial to a comet's identity.