In kilometers, 1 astronomical unit (AU) is approximately how far from Earth?

• A. About 200 million kilometers
• B. About 150 million kilometers
• C. About 1 billion kilometers
• D. About 15 million kilometers

Answer: (B)

An astronomical unit represents the average distance from Earth to the Sun. That distance is about 149.6 million kilometers, so it’s commonly rounded to 150 million kilometers. Because Earth’s orbit is slightly elliptical, the distance varies a bit—from roughly 147 million to about 152 million kilometers—but 150 million is the standard reference. Among the options, the one closest to 150 million kilometers fits best. The other numbers are noticeably off: 200 million is too far, 1 billion is far too large, and 15 million is far too small.