Astronomy current events question: damped Lyman alpha systems

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!)

Jessica Hales, "New Method Solves 40 Year-Old Mystery on the Size of Shadowy Galaxies" (January 6, 2016)
swinburne.edu.au/news/latest-news/2016/01/new-method-solves-40-year-old-mystery-on-the-size-of-shadowy-galaxies.php

Light from background galaxies can be used to map damped Lyman alpha systems (DLAs), which are ancient:
(A) cold gas clouds.
(B) metal-rich stars.
(C) alien structures.
(D) red dwarfs.
(E) big bang ripples.

Correct answer: (A)

Student responses
Sections 30678, 30679, 30680
(A) : 34 students
(B) : 2 students
(C) : 0 students
(D) : 4 students
(E) : 7 students