Astronomy current events question: supernovae remnants on Earth's ocean bottoms

Astronomy 210L, spring semester 2016
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!)

Phil Dooley, "Supernovae Showered Earth with Radioactive Debris" (April 7, 2016)
anu.edu.au/news/all-news/supernovae-showered-earth-with-radioactive-debris

Material found on Earth's ocean bottoms may be remnants of two nearby recent supernova explosions, as determined from its:
(A) speed and trajectory.
(B) radioactivity.
(C) neutrino emissions.
(D) lack of organic compounds.
(E) electrostatic charge.

Correct answer: (B)

Student responses
Sections 30678, 30679, 30680
(A) : 1 students
(B) : 12 students
(C) : 5 students
(D) : 10 students
(E) : 3 students