Your Weird Cousin, Who Is Really into Astronomy, Decides That

Multiple Choice

Your weird cousin, who is really into astronomy, decides that the return address he uses on his letters is incomplete! To his city, state, and country, he begins to add: "North America, Earth, Solar System..." If he now wants to include the name of the Galaxy's spiral-structure feature in which the Earth is located, how should his address end?

A) Cygnus Arm
B) Orion Spur
C) Perseus Arm
D) Sagittarius-Carina Arm
E) Mars arm
Section 25.3: The Mass of the Galaxy