Polygon abcd goes through a sequence of rigid transformations to form polygon a′b′c′d′. the sequence of transformations involved is a reflection across the

X axis because of its sequence that it is involved with a reflection which is a transformation

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.