Ultraviolet radiation from the sun can damage not only eyelid skin but

Hi Doer01

In Conclusion/Inference question type, we are looking for a guaranteed 100% correct stated/inferred information in the passage.
In Assumption question type, we are looking for UNTOLD necessary information to link premise with a conclusion (filling a gap).

The question we are discussing is Inference type.

(C) is an assumption built on the info that "lenses MAY make the hues in traffic lights difficult to discriminate"
here there are 2 problems:
1. although the passage used "MAY make", option "C" used "SHOULDN'T" as if it is a 100% certain threat --> Language strength is very important
2. Our task is not to assume, but to infer an information we can be 100% sure of.

(D) is a correct inference based on solid info from the passage.
The passage discusses "Blue-blocking sunglass" (which is some kind of eyeglasses);
and mentions that "NOT ALL blue-blocking lenses offer adequate UV protection" (which means that the eyeglass MAY not be able to protect its wearer from UV),
and warned that "Ultraviolet radiation from the sun can damage not only eyelid skin but also the cornea and conjunctiva" (which are examples of eye problems).

why D is correct?:
1. it is not as assumption, but a rephrasing for information already stated.
2. suitable language strength (Not all ---> May)