The correct answer is: C. Water hyacinth
Water hyacinth is a free-floating aquatic plant that is native to South America. It is an invasive species that has spread to many parts of the world, including Africa, Asia, and Australia. Water hyacinth can form dense mats that block sunlight and prevent other plants from growing. It can also clog waterways and make it difficult for boats to navigate.
Water hyacinth is an effective bioindicator of water pollution. It can absorb heavy metals, pesticides, and other pollutants from the water. It can also remove nutrients from the water, which can help to reduce algae blooms.
Water hyacinth can be used to control water pollution in a number of ways. It can be used to create biofilters, which are systems that use plants to remove pollutants from the water. It can also be used to create floating wetlands, which are areas of water that are covered with plants. Floating wetlands can help to improve water quality by filtering out pollutants and providing habitat for fish and other aquatic life.
Water hyacinth is a valuable tool for controlling water pollution. It is an effective bioindicator of pollution and can be used to create biofilters and floating wetlands.