Astronomy current events question: Earth's Trojan asteroid

Astronomy 210L, fall semester 2011
Cuesta College, San Luis Obispo, CA

Students are assigned to read online articles on current astronomy events, and take a short current events quiz during the first 10 minutes of lab. (This motivates students to show up promptly to lab, as the time cut-off for the quiz is strictly enforced!)

Alasdair Wilkins, "Earth’s First Known Trojan Asteroid Follows Our Orbit Like a Second Earth," July 27, 2011
http://io9.com/5825269/earths-first-known-trojan-asteroid-follows-our-orbit-like-a-second-earth

Asteroid 2010 TK7 was recently discovered to be a Trojan asteroid of Earth, meaning that it:
(A) is on a future collision path with Earth.
(B) protects Earth from smaller asteroids.
(C) was first observed in Ancient Greek times.
(D) moves along with Earth around the sun.
(E) may be a second Earth fragment from the opposite side of the sun.

Correct answer: (D)

Student responses
Sections 70178, 70186, 70200
(A) : 8 students
(B) : 4 students
(C) : 1 student
(D) : 41 students
(E) : 6 students