To prove a theorem of geometry using rule-based systems, represent the follow- ing statements as production rules: a. Corresponding sides of two congruent triangles are also congruent. b. Corresponding angles of two congruent triangles are also congruent. c. If corresponding sides of two triangles are congruent then the triangles are congruent. d. If corresponding sides and the angle covered by them are equal then the triangles are congruent. e. Base angles of an isosceles triangle are congruent.