Why do astronomers use astronomical units (AU) instead of kilometers (km)?(1 point)

Question

Responses

AU is used for spacing, while km is used for length.
AU is used for spacing, while km is used for length.

Large distances are easier to express in AU than in km.
Large distances are easier to express in AU than in km.

AU is used in astronomy, while km is used in physics.
AU is used in astronomy, while km is used in physics.

There are no km in outer space, only AU.

Answer 1

Large distances are easier to express in AU than in km.