A researcher tracks the escape behavior of a population of squirrels on campus across two ...

A researcher tracks the escape behavior of a population of squirrels on campus across two generations.
 
  When she plots the escape behavior of the offspring generation against the parental behavior, she notes that the offspring's behavior exactly matches the parental behavior. Nonetheless, the narrow-sense heritability equals zero. How can the heritability equal zero in this example?
  a. The additive genetic variance equals zero.
  b. All the escape behavior alleles are fixed in the population.
  c. There is no phenotypic variation.
  d. A and B.
  e. All of the above.