Astronomy current events question: Earth life started on Mars?

Astronomy 210L, fall 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!)

Alan Boyle, "'We Are All Martians': Chemist's Otherworldly Claim Stirs Debate," August 28, 2013
http://www.nbcnews.com/science/we-are-all-martians-chemists-otherworldly-claim-stirs-debate-8C11026339

Researchers speculate that life on Earth first started on Mars before being transported here, based on analysis of __________ in Martian meteorites.
(A) building-block minerals.
(B) radioactive isotopes.
(C) carbon nanostructures.
(D) fossil microorganisms.
(E) chlorophyll residue.

Correct answer: (A)

Student responses
Sections 70178, 70186, 70200
(A) : 34 students
(B) : 5 students
(C) : 11 students
(D) : 8 students
(E) : 1 student