Astronomy current events question: hydrogen-volcano greenhouse effect?

Astronomy 210L, spring semester 2017
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!)

Rebecca Valli, "Volcanic Hydrogen Spurs Chances of Finding Exoplanet Life" (February 27, 2017)
mediarelations.cornell.edu/2017/02/27/volcanic-hydrogen-spurs-chances-of-finding-exoplanet-life/

Scientists propose that planets with hydrogen-spewing volcanoes could create conditions that harbor life, by producing:
(A) hydrocarbon nutrients.
(B) protective ozone.
(C) flammable lava.
(D) a greenhouse effect.
(E) ingredients for water oceans.

Correct answer: (D)

Student responses
Sections 30679, 30680
(A) : 7 students
(B) : 2 students
(C) : 1 student
(D) : 19 students
(E) : 3 students