Step 1: Concept
Sex determination varies across the animal kingdom.
Step 2: Meaning
Haplodiploidy is a system where the number of chromosome sets determines sex.
Step 3: Analysis
In honeybees, fertilized eggs (diploid) develop into females (queens/workers), while unfertilized eggs (haploid) develop into males (drones).
Step 4: Conclusion
Sex in honeybees is determined by haplodiploidy.
Final Answer:(D)