I think you are getting confused between the answers. I said A-C would be all be acceptable because some people, who are usually uppper-class and speak more formally, use articles in that way. You had previously said B would be unacceptable.
As for mixing singular and plural nouns, I'm not saying "it would be understood" and therefore acceptable, I'm saying "it would be understood to mean...". There are no hard and fast rules regarding the matter, it's a matter of style and logic. As I said "Hikers should bring bottles of water on their trip" could be understood to mean each hiker should bring more than one bottle, and would be the more logical conclusion. Using the singular noun in this example makes the sentence much easily understood as it was supposed to be, as I said, in the "each one" sense.