Square ABCD is shown with four congruent images such that ABCD Is congruent to FGHI Is congruent to JKLM Is congruent to NOPQ Is congruent to RSTU. On a coordinate plane, triangle A B C D is reflected across the x-axis to form triangle R S T U.

For which square is a reflection necessary to produce the transformed figure?
FGHI
JKLM
NOPQ
RSTU