Astronomy current events question: habitable-zone planet GJ 667Cc

Astronomy 210L, spring semester 2012
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!)

Irene Klotz, "New Alien Planet Ripe for Life?," February 2, 2012
http://news.discovery.com/space/exoplanet-gj667cc-120202.html

Researchers discovered GJ 667Cc, a planet where liquid water may exist, by analyzing:
(A) water vapor trails.
(B) its overall density.
(C) tidal patterns.
(D) light reflected by oceans.
(E) wobbles in the star it orbits.

Correct answer: (E)

Student responses
Sections 30678, 30679, 30680
(A) : 10 students
(B) : 6 students
(C) : 6 students
(D) : 8 students
(E) : 26 students