What is the definition of an analogy per the LSAT?

I eliminated answer choice (E) due to the verbiage, "An argument from analogy" largely because the definition of analogy I had been using didn't fit with the argument being employed in the stimulus. In the traditional definition of analogy, I had been assuming that an analogy would compare two relatively dissimilar phenomena that were both connected by a common principle while not being a difference in kind. However, in this stimulus, the two phenomena being compared are a drug's physiological mechanism and the chemical composition. Normally, I wouldn't consider these two things to be an analogy. Instead, if what was being compared was a drug's physiological mechanism (An external entity having an impact on the inner workings of a given thing) and a consultant hired to change customer service operations at a company (See parenthetical aside above) I would consider that an analogy. Having said all that, can someone please help me understand what is and is not considered an analogy by standards of the LSAT so I don't miss additional questions due to something silly like a misunderstanding of the definition of a word? Thank you in advance.