Step-by-step explanation:
1. m = (9-3)/(2-1) = 6/1 = 6 => B
2. m = (-7-5)/(2+1) = -12/3 = -4 => G
3. the horizontal line passes (0,4) => m = 0 =>I
4. m = (2-1)/(8-8) = 1/0 = oo => undefined => A
