Excessive sand mining from riverbeds can lead to:

The correct answer is: d) All of the above.

Excessive sand mining from riverbeds can lead to a number of problems, including:

• Riverbank erosion: When sand is removed from a riverbed, the riverbank becomes unstable and can erode more easily. This can lead to flooding, landslides, and other problems.
• Lowering of the water table: Sand helps to filter and store water in the ground. When sand is removed, the water table can lower, which can lead to problems for people who rely on groundwater for drinking, irrigation, or other purposes.
• Ecological imbalances: Sand is an important part of many ecosystems. When sand is removed, it can disrupt the balance of these ecosystems and lead to problems for plants and animals.

In conclusion, excessive sand mining from riverbeds can have a number of negative consequences. It is important to carefully consider the environmental impact of sand mining before undertaking any such projects.