Genetic drift, the founder principle, and the bottleneck effect all occur under what conditions?
a. in small populations when one genetic trait becomes more common in a population purely by chance
b. in small populations and result in a decrease in genetic diversity and/or an increase in the occurrence of specific genetic traits
c. when a small group of organisms only reproduce with each other to create a larger population of organisms
d. when the majority of a population is decimated and there are only a few remaining organisms left to rebuild the population