Answer: Last Option (Affects All)
Reason: People may think it may be the last one because it has the most, but in fact, it affects all. When the population finds mates, and have babies, that increases the population, and over a period of time, with the limited space, it's going to be bad. The last one (C) will fill up the space faster, as there are more mates, meaning territorial problems, and babies. The first one (A) has less population, and will fill up in the most amount of time, but it still has the same process and outcome. I hope this helps. :)