Astronomy current events question: plausible habitable Proxima b models

Astronomy 210L, fall semester 2016
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!)

Bastien Brugger, Olivier Mousis, and Magali Deleuil
, "Proxima b, an Exoplanet Covered with an Ocean?" (October 6, 2016)
insu.cnrs.fr/node/6047 (Google translation)

A French-American research team proposed plausible habitable compositions and sizes of exoplanet Proxima b, based on the planet's measured:
(A) rotation rate.
(B) cloud cover.
(C) reflectivity.
(D) atmospheric density.
(E) mass.

Correct answer: (E)

Student responses
Sections 70178, 70186
(A) : 3 students
(B) : 1 student
(C) : 4 students
(D) : 7 students
(E) : 13 students