<span>Instead, in 1857, in the case of Dred Scott v. Sanford, the United States Supreme Court declared that all blacks — regardless of whether they were slaves or free men — were not and could never become citizens of the United States. The court also ruled that the 1820 Missouri Compromise was unconstitutional.</span><span>Dec 13, 2010</span>
Explanation:
Mezzotint is a technique of engraving areas of tone rather than lines. In this method, the entire surface of the plate is roughened by a spiked tool called a rocker so that, if inked at that point, the entire plate would print in solid black. ....................Hope we can be friends :)
A. sounds the most reasonable.