First, we can eliminate d(x) because we can see it's a linear line. We can also eliminate a(x) because it's also a linear line. Both b(x) and c(x) have an asymptote. on b(x) you can see that x = 3 is the asymptote. For c(x) if it's graphed, it has a horizontal asymptote at y = -1.
Hope this helps!
