Respuesta :
Answer C: A condition of agreement.
The meaning of the word "concord" as it is used in the sentence "...but our concord hath withstood ourtroubles, and fixes a memorable era for posterity to glory in." is 'condition of agreement'. [Formal]It is the state of having a friendly relationship, so that you agree on things and live in peace." It's the opposite of 'discord' : "a state of not agrreing or sharing opinions."