Which of the following is considered an Aquatic Nuisance Plant?

An aquatic nuisance plant is typically defined as a non-native species that can disrupt local ecosystems, impede waterway navigation, or adversely affect water quality. Purple loosestrife is a prime example of such a plant. It is native to Europe and Asia but has spread aggressively in North America, outcompeting native vegetation and altering wetland habitats. This plant's dense growth can reduce the diversity of species in the area and negatively impact wildlife that depends on native plants for food and shelter.

The other options listed do not fit the classification of aquatic nuisance plants. Zebra mussels, for instance, are invasive mollusks that can cause significant ecological and economic harm, but they are not classified as plants. Similarly, the Asian tiger mosquito is an insect known for its role as a pest and vector for disease rather than as an aquatic nuisance species. The spiny water flea, another invasive organism, is a type of zooplankton affecting aquatic ecosystems but, like the zebra mussel, is not a plant. Thus, purple loosestrife is accurately identified as an aquatic nuisance plant.