We Know the Properties of Hydrogen Atoms Well from Studying

We know the properties of hydrogen atoms well from studying them in laboratories on Earth. A fundamental idea in astronomy is that:

A) a hydrogen atom anywhere else in the universe is the same as it is here.
B) hydrogen atoms change in regular and predictable ways as they get farther from Earth.
C) the characteristics of hydrogen atoms follow different rules in different galaxies, but these can be predicted by studying the properties of each galaxy as a whole.
D) hydrogen atoms are unique to our solar system and the manner in which it was formed.