Nebula is the correct answer.

Explanation:
Interstellar cloud:
An interstellar cloud refers to a region in space that contains various elements such as dust, hydrogen, helium, and other gases. These clouds are found in the vast spaces between stars within a galaxy. They are considered to be the raw material for the formation of stars and planetary systems.

Composition:
Interstellar clouds are composed of tiny solid particles, known as dust, along with various gases. The main gases present in these clouds are hydrogen and helium, which are the most abundant elements in the universe. Apart from these, interstellar clouds may also contain traces of other elements such as carbon, nitrogen, oxygen, and heavy metals.

Nebula:
A nebula is a term used to describe an interstellar cloud of dust, hydrogen, helium, and other gases. It is derived from the Latin word for "cloud." Nebulae are often vast in size, spanning several light-years across. They can be observed as diffuse patches of light in the night sky.

Types of Nebulae:
There are different types of nebulae, each with its own characteristics. Some common types include:

1. Emission Nebulae: These nebulae are composed of ionized gas that emits light of various colors. The most famous example is the Orion Nebula.

2. Reflection Nebulae: These nebulae do not emit their own light but instead reflect the light of nearby stars. They often appear blue in color due to the scattering of shorter wavelengths of light.

3. Dark Nebulae: These nebulae are dense regions of dust and gas that block the light from more distant stars. They are often seen as dark patches against the background of bright stars.

4. Planetary Nebulae: These nebulae are formed when a dying star sheds its outer layers, creating a glowing shell of gas around the central core.

Formation of Stars:
Nebulae play a crucial role in the formation of stars. The gravitational collapse of interstellar clouds leads to the formation of protostars, which eventually evolve into fully-fledged stars. The dust and gas within the nebulae clump together under their own gravity, creating dense regions where stars are born.

In conclusion, an interstellar cloud of dust, hydrogen, helium, and other gases is termed as a nebula. These nebulae serve as the birthplace of stars and planetary systems, providing the necessary raw materials for their formation.