Final answer:
Plant viruses can be transmitted through various vectors, including insects, nematodes, contaminated seeds, and humans. All of the choices listed (worms, contaminated seeds, humans, and insects) are correct methods of transmission for plant viruses.
Step-by-step explanation:
Plant viruses may be transmitted by a variety of vectors. These include insects such as aphids and whiteflies that mechanically transfer viruses from one plant to another, the soil-inhabiting nematodes or fungi that can carry viruses, or through contaminated seeds that carry viruses to the next generation of plants, which is an example of vertical transmission. Humans can also play a role in the transmission of plant viruses through activities such as farming, pruning, or landscaping that can cause mechanical damage to plants, hence allowing virus entry. Additionally, sometimes plant viruses are spread when an infected plant comes in direct contact with a healthy one, transferring sap that carries the virus.
Therefore, plant viruses may be transmitted by worms (nematodes), contaminated seeds, humans, and insects. In summary, the answer to the question is E) All of the choices are correct.