To solve this question, the user needs to be familiar with different types of flies and their characteristics.
Now, let's go through each option and explain why it is right or wrong:
A. Dragonfly: This option is incorrect. Dragonflies are not pests and they do not carry diseases or viruses.
B. Horsefly: This option is incorrect. Horseflies are known for biting and causing pain, but they do not carry as many diseases as the answer choice.
C. Firefly: This option is incorrect. Fireflies are not pests and they do not carry diseases or viruses.
D. Housefly: This option is correct. Houseflies are the most common of all flies and are considered pests. They are known to carry many diseases and viruses and can be harmful to human health.