Astronomy current events question: WASP-94 "cousin" planets

Astronomy 210L, fall 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!)

waspplanets@gmail.com, "WASP-94: 'Cousin' Planets Around Twin Stars," (September 30, 2014)
http://wasp-planets.net/2014/09/30/wasp-94-cousin-planets-around-twin-stars/

The Wide-Angle Search for Planets telescopes discovered that binary system stars WASP-94A and WASP-94B are each orbited by a Jupiter-sized extrasolar planet, by observing these planets:
(A) wobbling their stars.
(B) colliding with each other.
(C) being torn apart by tidal forces.
(D) passing in front of their stars.
(E) emitting infrared light.

Correct answer: (D)

Student responses
Sections 70178, 70186
(A) : 3 students
(B) : 2 students
(C) : 3 students
(D) : 25 students
(E) : 6 students