Astronomy current events question: exoplanet Kepler-1625b's moon?

Astronomy 210L, fall semester 2018
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!)

Felicia Chou, Ray Villard, and Alison Hawkes, "Astronomers Find First Evidence of Possible Moon Outside Our Solar System" (October 3, 2018)
nasa.gov/press-release/astronomers-find-first-evidence-of-possible-moon-outside-our-solar-system

NASA's Kepler Space Telescope may have identified a moon orbiting exoplanet Kepler-1625b as it __________ their star.
(A) collided with.
(B) passed in front of.
(C) reflected light from.
(D) broke away from.
(E) gravitationally pulled on.

Correct answer: (B)

Student responses
Sections 70178, 70186
(A) : 2 students
(B) : 15 students
(C) : 6 students
(D) : 0 students
(E) : 2 students