Which of the Following Illustrates Emerson's Observation That "To Be

Which of the following illustrates Emerson's observation that "to be understood is a rare luxury"?

A) The phrase "public safety" is clearly understood, because everyone knows the meaning of both words.
B) The phrase "public safety" is rarely used, because the concept of security is an ethical norm.
C) The phrase "public safety" represents an ethical norm that is a rare luxury, because the public rarely feels safe.
D) The phrase "public safety" seems clear at first glance, but on pondering its various interpretations, one realizes that it is not so clear.