Which of the following groups of organisms are parasites plants?

The question is asking about the types of organisms that can be parasites to plants. A parasitic plant is one that derives some or all of its nutritional requirement from another living plant. They can be harmful to their host plants by taking necessary nutrients, and they can also cause diseases.

The correct answer is Option C: Dodder, fungus and striga.

Dodder is a type of parasitic plant that wraps itself around a host plant to extract water and nutrients. It doesn't have leaves or roots and relies completely on its host for survival.

Fungi are also known parasites of plants. While some species of fungi have beneficial relationships with plants, others are parasitic, causing diseases. They invade the plant's tissue and extract nutrients, often harming or even killing the plant in the process.

Finally, Striga, also known as witchweed, is a genus of parasitic plants that attach to the roots of host plants and extract nutrients and water. They are particularly harmful to grain crops in Africa.

While organisms like nematodes and bacteria (option A and D) can be harmful to plants, they are not considered parasitic plants because they are not plants themselves. Similarly, while mistletoe (option D) is a parasitic plant, it's not a fungus or bacterium, so option D is not entirely correct.