Task: Class Definition Understanding (ontology: Earth_Environment/EnvironmentOntology)

Which of the following definitions best describes 'astronomical object'?

A. An interstellar cloud of dust, hydrogen, helium and other ionized gases
B. An object which is naturally occuring, bound together by gravitational or electromagnetic forces, and surrounded by space.
C. An astronomical object which is composed of dense gas and dust rotating around a young newly formed star, a T Tauri star, or a Herbig Ae/Be star in a disk-shaped configuration.
D. An object which is composed of one or more gravitationally bound structures that are associated with a position in space.

Answer: An object which is composed of one or more gravitationally bound structures that are associated with a position in space.