Solution

Haploid-diploid mechanism or Haplodiploidy is a unique phenomenon in which an unfertilized egg develops into a male and a fertilized egg develops into a female. Therefore, the female is diploid (2n), and the male is haploid (n). Eggs are formed by meiosis and sperms by mitosis. Fertilization restores the diploid number of chromosomes in the zygote which gives rise to the female, If the egg is not fertilized, it will still develop but into a male (arrhenotoky or arrhenotokous parthenogenesis). It is seen in hymenopterous insects, such as bees, wasps, saw flies and ants. So, the correct answer is 'Honeybees, ants and wasps'.