Which Would Be an Example of a Density-Dependent Limiting Factor

Which would be an example of a density-dependent limiting factor?

A) A flood kills all the people in a densely populated city, but few in the less densely populated countryside.
B) The more mice there are on an island, the less food each has to eat.
C) The more mice there are on an island, the more rapidly the population grows.
D) As the number of people on the Earth increases, many other kinds of organisms go extinct.