Astronomy current events question: TRAPPIST discovery of three habitable zone exoplanets

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!)

Michaël Gillon, "Life Elsewhere in the Universe? A New Nearby Planetary System Could Bring Soon the Answer..." (May 2, 2016)
ulg.ac.be/cms/c_7453882/en/life-elsewhere-in-the-universe-a-new-nearby-planetary-system-could-bring-soon-the-answer

The TRAPPIST robotic telescope discovered three habitable zone exoplanets as they __________ their ultra-cool dwarf star.
(A) gravitationally pulled.
(B) broke away from.
(C) collided with.
(D) passed in front of.
(E) reflected light from.

Correct answer: (D)

Student responses
Section 30680
(A) : 0 students
(B) : 5 students
(C) : 0 students
(D) : 4 students
(E) : 4 students