The correct answer is D. show only outward respect.
To pay lip service to something means to say that you support it but not actually do anything to show that you do. In the context of the question, some people are wondering whether we only say that we support democracy but don’t actually do anything to support it.
Option A, pay oral tribute, is similar to paying lip service, but it is more specific in that it refers to giving verbal praise or admiration. Option B, attach no value, means to not consider something to be important or valuable. Option C, remain indifferent, means to not care about something or to be neutral about it.