The correct option is
C The gene pool remain constant
Hardy-Weinberg independently formulated a rule that relates allelic and genotypic frequencies in a population. The Hardy-Weinberg equilibrium rule states that the allelic frequencies at an autosomal locus in a population will not change i.e. remain constant and stable from one generation to the next generation i.e gene pool (the sum total of alleles of the particular gene present in a population remain constant).
So, the correct answer is option C, The gene pool remain constant.