Astronomy current events question: young "yellowball" stars

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, "Citizen Scientists Lead Astronomers to Mystery Objects in Space," (January 27, 2015)
http://www.jpl.nasa.gov/news/news.php?feature=4462

Internet volunteers discovered "yellowballs" in NASA's Spitzer Space Telescope data, which may be __________ massive stars.
(A) slowly dying.
(B) gas giants orbiting.
(C) black holes swallowing.
(D) early formation stages of.
(E) rapidly approaching.

Correct answer: (D)

Student responses
Sections 30678, 30679, 30680
(A) : 2 students
(B) : 4 students
(C) : 1 student
(D) : 42 students
(E) : 2 students