Astronomy current events question: waves on Titan's shores?

Astronomy 210L, spring semester 2016
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!)

News release, "Mystery Feature Evolves in Titan's Ligeia Mare" (March 2, 2016)
jpl.nasa.gov/spaceimages/details.php?id=PIA20021

Analysis of NASA's Cassini spacecraft images of the changing hydrocarbon sea coast on Saturn's moon, Titan, indicate that it may be caused by:
(A) waves.
(B) volcanic eruptions.
(C) tectonic plate motion.
(D) moonquakes.
(E) water icebergs.

Correct answer: (A)

Student responses
Sections 30678, 30679
(A) : 15 students
(B) : 1 student
(C) : 5 students
(D) : 1 student
(E) : 1 student