The effect of the Crimean war was to (A) allow Russia to retain control of Moldavia and Walachia
(B) plunge the Estonian economy into a long period of decline
(C) strengthen the Concert of Europe with the addition of France
(D) destroy the Concert of Europe and leave Russia without allies

Correct answer is (D) destroy the Concert of Europe and leave Russia without allies .

Explanation:

Option A is not correct as this two principalities were unified just a couple of years later into Romania.

Option B is not correct as this war didn't affected Estonia.

C is not correct as quite on the contrary this was one of the crisis that undermined the Concert of France.

D is correct as European forces, especially Austria, Britain and France were afraid that Russian influence and conquering of Constantinople would totally change the balance of powers.

c

the articles of confederation placed most of the power on the feds

answer; taking up arms to defend the nation;