Astronomy current events question: Mercury's north pole ice

Astronomy 210L, fall semester 2014
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!)

Paulette Campbell, "MESSENGER Provides First Optical Images of Ice Near Mercury’s North Pole," (October 15, 2014)
http://www.jhuapl.edu/newscenter/pressreleases/2014/141015.asp

NASA's MESSENGER spacecraft obtained images of __________ in craters near Mercury’s north pole.
(A) tectonic fault lines.
(B) fresh magma.
(C) frozen ice.
(D) collapsed lava tubes.
(E) water vapor geysers.

Correct answer: (C)

Student responses
Sections 70178, 70186
(A) : 1 student
(B) : 2 students
(C) : 31 students
(D) : 1 student
(E) : 0 students