The option that touches the border of Iran is [A] Caspian Sea. Stretching along Iran’s northern coastline, the Caspian Sea is a significant geographical feature and the largest enclosed inland body of water on Earth. It serves as a vital resource for Iran, supporting various industries and ecosystems along its coastline, and plays a crucial role in the country’s economy and geopolitical dynamics. The Caspian Sea’s strategic importance has made it a focal point for international negotiations and agreements among the countries bordering its shores, including Iran, Azerbaijan, Russia, Kazakhstan, and Turkmenistan.