Astronomy current events question: Large Underground Xenon dark-matter detector results

Astronomy 210L, fall semester 2013
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!)

Eugenie Samuel Reich, "No Sign of Dark Matter in Underground Experiment," October 30, 2013
http://www.nature.com/news/no-sign-of-dark-matter-in-underground-experiment-1.14057

The Large Underground Xenon (LUX) experiment has not yet detected anything, which is evidence that dark matter:
(A) has an extremely long radioactive half-life.
(B) completely decayed into dark energy.
(C) is weaker or less massive than expected.
(D) does not gravitationally interact with Earth's core.
(E) repels xenon atoms.

Correct answer: (C)

Student responses
Sections 70178, 70186
(A) : 4 students
(B) : 0 students
(C) : 30 students
(D) : 3 students
(E) : 2 students