Which expression shows (3-4i)+(-7-8i) in simplest form?
A.-1-15i
B.-4-12i
C.-4-28i
D.10-12in

The first one, i believe, would be correct. all the others have one thing in common, and that's that they have repeating numbers. in the second one, x and y have repeating 6's and 3's, and in the third, x and y have repeating 6's as well. in the last one, there are repeating 3's. the first one has no repeating numbers.