Here is a usage and mechanics question that I need help understanding:
Change the italicized portion with the best replacement, or choose A if correct.
When light from a distant source, such as the sun, it strikes a collection of water drops, such as rain, spray, or fog, a rainbow many appear.
A. such as the sun, it strikes
B. like the sun's striking
C. such as the sun, and striking
D. such as the sun, strikes
E. like the sun's strikes
For this question I chose E, because it seems as though light is being being expanded upon, so you would give the light from the sun as an example, rather than the sun itself. Also, strikes fixes the comma splice. Anyway, the correct answer is D. I think is so because the set off phrase within the commas is giving an example of a source, rather than an example of light.
Essentially, my question is how can I know when the set off phrase (by the way, what are those types of phrases called; the ones of the form "such as the sun"?) modifies the word "source" or "light"? I'm thinking that it modifies "source" because it is adjacent to it, but I want a deeper explanation than that.