Astronomy current events question: measuring Proxima Centauri's mass

Astronomy 210L, spring semester 2014
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!)

Ken Croswell, "Proxima’s Unprecedented Passage: When Stars Align," January 23, 2014
http://www.scientificamerican.com/article/proximae28099s-unprecedented-passage-when-stars-align/

Later this year the nearby red dwarf star Proxima Centauri will __________, allowing its mass to be measured.
(A) explode as a type Ia supernova.
(B) pass in front of a distant star.
(C) be captured by our solar system.
(D) complete its first observed rotation.
(E) be eclipsed by the moon.

Correct answer: (B)

Student responses
Sections 30678, 30679, 30680
(A) : 1 student
(B) : 43 students
(C) : 3 students
(D) : 5 students
(E) : 1 student