Problem 4. Following sentences are given in the knowledge Base. 1. Vx Vy (-Mammal(x) v-Bird(y)) v Smarter (x, y) 2. Vx Chicken(x) => Bird (x) 3. Vx x Dog(x) => Mammal(x) 4. Chicken (Coco) Does Smarter (Chris, Coco)? Use Forward Chaining to prove your answer and state which inference rules you used in each step. (20 pts)