Can somebody help me with this ?

C. It discouraged the British from supporting the Confederacy

Explanation:

The British abolished slavery years before the US, so it would look very wrong for the UK to support the confederacy, who were the ones who preserved slavery.  This also wouldn't set well with the public which would erupt some protests across the nation, and the US also could've invaded Canada and that also would've been bad for the British because wars were expensive.

c it says nothing about connecting those 2 seas.

religion played a major role in the american revolution by offering a moral sanction for opposition to the british--an assurance to the average american that revolution was justified in the sight of god. the revolution strengthened millennialist strains in american.