As a result of habitat destruction, the size of the Florida panther population has been drastically reduced. It is estimated that there are only 100 to 160 Florida panthers in the wild. Which statement best explains why the Florida panther population may not continue to evolve?
(1) There is no longer a chance of mutations occurring in the population.
(2) There is a lack of competition for limited environmental resources.
(3) There is no longer a chance of a trait providing a reproductive advantage to the population.
(4) There is a lack of genetic variation for selec-tion to act upon.

Option D, There is a lack of genetic variation for selection  to act upon

Explanation:

Genetic variation defines the differences with in the organism of the same species and have been a driving force for selection.  

Since the population of panther has reduced to a very small number, it is very obvious that the gene pool has also reduced which in turn has reduced the genetic variation and hence the lack of genetic variation induces inbreeding depression which further restricts evolution.

Hence, option D is correct

your answer should be c) enjoy!

b - the respond is innate and varies over time.

good luck!