Astronomy current events question: ringwoodite and water beneath Earth's crust

Astronomy 210L, spring 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!)

Bryan Alary, "Rare Mineral Points to Vast 'Oceans' Beneath the Earth," March 12, 2014
http://news.ualberta.ca/newsarticles/2014/march/rare-mineral-points-to-vast-oceans-beneath-the-earth

An international team of scientists discovered a mineral in a diamond which indicates:
(A) it was not created by volcanic heat and pressure.
(B) Earth's oceans came from comet impacts.
(C) carbon-based life began in volcanic ocean vents.
(D) diamonds are extremely common.
(E) large amounts of water lie under Earth's crust.

Correct answer: (E)

Student responses
Sections 30678, 30679, 30680
(A) : 7 students
(B) : 2 students
(C) : 3 students
(D) : 0 students
(E) : 30 students