At an Underdominant Locus,how Will Allele Frequencies Change Through Time

Multiple Choice

At an underdominant locus,how will allele frequencies change through time?

A) The homozygote with the greatest fitness advantage will have its allele fixed.
B) A balanced polymorphism of both alleles will be maintained at a stable equilibrium.
C) The homozygote with the lowest fitness advantage will have its allele lost.
D) One or the other allele will be lost depending on their initial frequencies.
E) Both alleles will be lost.