Astronomy current events question: Large Underground Xenon experiment

Astronomy 210L, fall 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!)

Bill Harlan, "Dark Matter Detector Submerged in Water Tank," November 15, 2012
http://www.sanfordlab.org/news/press_release/dark-matter-detector-submerged-water-tank

The Large Underground Xenon experiment in South Dakota to detect dark matter is installed deep underground in a water-filled tank in order to:
(A) cool down its components.
(B) shield it from cosmic radiation.
(C) protect it from earthquake tremors.
(D) contain radioactive emissions.
(E) inhibit corrosion.

Correct answer: (B)

Student responses
Sections 70178, 70186, 70200
(A) : 2 students
(B) : 19 students
(C) : 1 student
(D) : 4 students
(E) : 0 students