For each integer N>1, there is a mathematical system in which two or more positive integers are defined to be congruent if they leave the same non-negative remainder when divided by N. If 69,90, and 125 are congruent in one such system, then in that same system, 81 is congruent to<spanclass=′latex−bold′>(A)</span>3<spanclass=′latex−bold′>(B)</span>4<spanclass=′latex−bold′>(C)</span>5<spanclass=′latex−bold′>(D)</span>7<spanclass=′latex−bold′>(E)</span>8