Astronomy current events question: curved, narrow gullies on Vesta

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!)

Elizabeth Landau, "Gullies on Vesta Suggest Past Water-Mobilized Flows," (January 21, 2015)
http://www.jpl.nasa.gov/news/news.php?feature=4453

Curved, narrow gullies observed by NASA's Dawn spacecraft on the surface of the large asteroid Vesta may be evidence of debris moved by __________ in the past.
(A) avalanches.
(B) volcanic flows.
(C) sinkholes.
(D) asteroid impacts.
(E) flowing water.

Correct answer: (E)

Student responses
Sections 30678, 30679, 30680
(A) : 2 students
(B) : 2 students
(C) : 1 student
(D) : 6 students
(E) : 52 students