Astronomy current events question: "next door" Earth-size planets?

Astronomy 210L, spring semester 2013
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!)

Michele Johnson, "Kepler Data Suggest Earth-size Planets May Be Next Door," February 6, 2013
http://www.nasa.gov/mission_pages/kepler/news/kepler-data-suggests-earth-size-planets-next-door.html

Astronomers at the Harvard-Smithsonian Center for Astrophysics estimate that Earth-size planets may be "next door," based on analyzing data from NASA's Kepler space telescope of planets orbiting:
(A) stars about to undergo type II supernova explosions.
(B) our sun, out beyond Pluto.
(C) red dwarf stars.
(D) sun-like stars.
(E) massive stars.

Correct answer: (C)

Student responses
Sections 30678, 30679, 30680
(A) : 1 student
(B) : 3 students
(C) : 40 students
(D) : 6 students
(E) : 1 student