What do the data suggest about the effects of cane toads on the predatory behavior of black snakes in areas where the toads have been present for 40–60 years?
a. black snakes in areas where cane toads have been present for 40–60 years are just as likely to prey on cane toads as on native frogs.
b. black snakes will prey on cane toads in areas where cane toads have been present for 40–60 years, but not when offered a native frog instead.
c. black snakes will not prey on cane toads in areas where cane toads have been present for 40–60 years.

C. Black snakes will not prey on cane toads in areas where cane toads have been present for 40–60 years.

Explanation:

Cane toad secret a toxin called bufotoxin which is a defense mechanism against predators. These defense mechanism is capable of killing black snakes if they eat cane toads. Within a period of 40 to 60 years, the black snakes in these area will be aware of the presence of a toxin capable of killing them in cane toads and will not prey on them. This phenomenon is termed learned behavioral adaptation.

i believe it's c. the trait for large beaks will be passed on to future generations through natural selection.

since eventually smaller beaks would have to find another source of food or even eventually just die out from the lack of food.