Which triangle defined by three points on the coordinate plane is congruent with the triangle illustrated, and why? a) (-1, , , 4); because corresponding pairs of angles are congruent. b) (-2, -, -, -9); because corresponding pairs of angles are congruent. c) (-1, , , 4); because corresponding pairs of sides and corresponding pairs of angles are congruent. d) (-2, -, -, -9); because corresponding pairs of sides and corresponding pairs of angles are congruent.