Question

100,000 light years refers to...

• the size of the spirals with or galaxy (Milky Way)
• an approximate measure of the luminosity of the galaxy
• an approximate measure of the distance across the galaxy****

Answer 1

agree (but Googled :)
https://www.google.com/search?q=size+of+milky+way+galaxy+in+light+years&ie=utf-8&oe=utf-8