Astronomy current events question: extreme mass-ratio binaries

Astronomy 210L, spring semester 2015
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!)

Christine Pulliam, "Mismatched Twin Stars Spotted in the Delivery Room," (February 12, 2015)
https://www.cfa.harvard.edu/news/2015-06

Mismatched stars in extreme mass-ratio binaries in the Large Magellanic Cloud are identified when they:
(A) emit x-ray pulses.
(B) undergo nova explosions.
(C) produce solar flares.
(D) pass in front of each other.
(E) transfer hydrogen between them.

Correct answer: (D)

Student responses
Sections 30678, 30679, 30680
(A) : 3 students
(B) : 7 students
(C) : 8 students
(D) : 33 students
(E) : 2 students