Answer : The correct answer is -
The primary purpose of Hardy Weinberg's work was to calculate the allele and genotype frequency in a non evolving population (which does not experiences any evolutionary force).
A population is said to be in the Hardy Weinberg's equilibrium, when it follows the following conditions -
1) No mutation occurs in the population.
2) No natural selection operates.
3) There is random mating in the population.
4) Population size should be large.
5) There is no gene flow in the population.
In other words, genetic variation remains constant from one generation to another generation.
This law follows the following equation-
p+q = 1
where p represents frequency of dominant allele and q is the frequency of recessive allele.