Astronomy current events question: "microlensing" of distant exoplanet

Astronomy 210L, spring semester 2015
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!)

Whitney Clavin and Felicia Chou, "NASA's Spitzer Spots Planet Deep Within Our Galaxy" (April 14, 2015)
http://www.jpl.nasa.gov/news/news.php?feature=4550

Space and ground-based telescopes used "microlensing" to discover a distant gas giant planet, while it:
(A) creates gravity waves.
(B) undergoes gravitational collapse.
(C) is pulled into the Milky Way's central supermassive black hole.
(D) passes in front of a more distant star.
(E) emits microwaves.

Correct answer: (D)

Student responses
Sections 30678, 30679, 30680
(A) : 1 student
(B) : 3 students
(C) : 4 students
(D) : 41 students
(E) : 5 students