Which example illustrates an improper use of deductive reasoning? a. all girls in mrs. lopez’s class have brown hair. cassandra is in mrs. lopez’s class. therefore, cassandra has brown hair. b. all isosceles triangles have two congruent sides. abc is a triangle therefore abc two congruent sides. c. all residents of townsburg have a pet. josiah lives on the north side of townsburg. therefore, josiah has a pet. d. all rhombi have diagonals that intersect at right angles. a square is a type of rhombus. therefore, a square’s diagonals intersect at right angles.