Final answer:
The Amu Darya no longer reaches the Aral Sea due to water diversion for irrigation, which predominantly supports agriculture in the Karakum Desert. The correct current endpoint of the river is the Karakum (D).
Step-by-step explanation:
The end point of the Amu Darya river has been significantly altered due to human activities, particularly for irrigating agricultural lands. Historically, the Amu Darya flowed into the Aral Sea, but the river's waters have been heavily diverted for irrigation purposes, mainly to grow crops such as cotton. Consequently, the river no longer reaches its original destination, the Aral Sea. Instead, much of its water is used in areas like the Karakum Desert, as part of the massive Kara Kum Canal effort in Turkmenistan, to support agriculture. Therefore, the correct answer to where the Amu Darya ends today is: D. The Karakum