Astronomy current events question: Ebb and Flow GRAIL spacecraft

Astronomy 210L, spring 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!)

D. C. Agle, Dwayne Brown, and Caroline McCall, "NASA's Twin GRAIL Spacecraft Begin Collecting Lunar Science Data," March 7, 2012
http://www.nasa.gov/mission_pages/grail/news/grail20120307.html

NASA's twin GRAIL mission spacecraft Ebb and Flow, orbiting the moon, have now begun collecting data to:
(A) map the moon's gravitational field.
(B) evaluate future moon base sites.
(C) find subsurface ice.
(D) measure Earth's tides.
(E) detect incoming solar flares.

Correct answer: (A)

Student responses
Sections 30678, 30679, 30680
(A) : 13 students
(B) : 1 student
(C) : 6 students
(D) : 2 students
(E) : 3 students