If in One Population of Pupfish All of the Individuals

Multiple Choice

If in one population of pupfish all of the individuals have a blood pigment that is extraordinarily effective at carrying oxygen, but this trait is not seen in any of the other populations, what likely happened?

A) Because oxygen was low where these pupfish lived, a new allele for an effective blood pigment arose.
B) This population was lucky to have an individual with a random mutation for an effective blood pigment, and the frequency of this allele was increased in subsequent generations through natural selection.
C) The ancestral population probably had this type of blood pigment, but it was lost through genetic drift in the other 29 populations.
D) The other populations did not need this pigment, so they did not evolve it.