Which of these variables is likely to undergo the largest change ...

[Garrulous]

Which of these variables is likely to undergo the largest change in value as the result of a mutation that introduces a brand-new allele into a population's gene pool at a locus that had formerly been fixed?
A) average heterozygosity
B) nucleotide variability
C) geographic variability
D) average number of loci

[Hawke]

Hello

A is the answer.