Conceptest: Ozone umbrella analogy

and is replicated here as part of the SERC Pedagogic Service.
Question:
Which statement is the best analogy?
A. An umbrella is to rain as the stratosphere is to solar radiation.
B. An umbrella is to rain as the stratosphere is to ultraviolet radiation.
C. An umbrella is to rain as the ozone layer is to solar radiation.
D. An umbrella is to rain as the ozone layer is to ultraviolet radiation.
Student Responses:
These responses were collected from students (mostly freshmen, non-majors) in multiple large Earth Science classes (60+ students) at an open-enrollment, Midwestern university. N=147 students on first attempt; 157 after peer instruction.
A. 12% of students selected this answer on their 1st attempt; 4% after peer instruction.
B. 18% of students selected this answer on their 1st attempt; 5% after peer instruction.
C. 26% of students selected this answer on their 1st attempt; 11% after peer instruction.
D. 44% of students selected this answer on their 1st attempt; 80% after peer instruction.(correct)
References and Notes:
The use of ConcepTests and Peer Instruction is discussed in detail on the ConcepTest page.
McConnell, D.A., Steer, D.N. and Owens, K.A., 2003, Assessment and Active Learning Strategies for Introductory Geology Courses, Journal of Geoscience Education, 51(2), 205-216.
McConnell, D.A., Steer et al., 2006, Using Conceptests to Assess and Improve Student Conceptual Understanding in Introductory Courses, Journal of Geoscience Education, (54(1), 61-68.