Astronomy current events question: NWA 7325 meteorite from Mercury?

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, "The First-Ever Meteorite from Mercury?," February 1, 2013
http://www.skyandtelescope.com/community/skyblog/newsblog/The-First-Ever-Meteorite-from-Mercury-189374981.html

A University of Washington researcher will announce that the NWA 7325 meteorite recently discovered in Morocco may be a fragment of Mercury, due to its:
(A) extremely high density.
(B) large embedded crystals.
(C) cosmic ray exposed crust.
(D) high-temperature core.
(E) magnesium-rich, but iron-free composition.

Correct answer: (E)

Student responses
Sections 30678, 30679, 30680
(A) : 5 students
(B) : 4 students
(C) : 0 students
(D) : 0 students
(E) : 47 students