Astronomy current events question: source of water on Earth and the moon

Astronomy 210L, spring 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!)

Kelly Beatty, "Earth and Moon: Sharing a Drink," May 9, 2013
http://www.skyandtelescope.com/community/skyblog/newsblog/Earth-and-Moon-Sharing-a-Drink-206859621.html

Brown University researchers determined that asteroids may have provided most of the water on both Earth and the moon by analyzing traces of water trapped in:
(A) orbit between Earth and the moon.
(B) the moon's polar craters.
(C) volcanic rocks from the moon.
(D) the moon's core.
(E) astronaut spacesuit boots.

Correct answer: (C)

Student responses
Sections 30682
(A) : 0 students
(B) : 4 students
(C) : 17 students
(D) : 0 students
(E) : 0 students