Astronomy current events question: using the moon as a mirror

Astronomy 210L, spring semester 2012
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!)

Cheryl Gundy, "Hubble to Use Moon as Mirror to See Venus Transit," May 4, 2012
http://www.nasa.gov/mission_pages/hubble/science/transit-mirror.html

The Hubble Space Telescope is planning to observe the moon while Venus transits across the sun on June 5, in order to study:
(A) the composition of Venus' atmosphere.
(B) minute fluctuations in the moon's orbit.
(C) the moon's concurrent annular eclipse.
(D) the shape of Venus' shadow on the moon.
(E) evaporation of ice from the moon's polar caps.

Correct answer: (A)

Student responses
Section 30682
(A) : 10 students
(B) : 2 students
(C) : 1 student
(D) : 4 students
(E) : 0 students