The correct answer is - C. Amu Darya.
The Karakum Desert is a desert located in Central Asia, it is a so-called ''cold desert'', which means that it has very high temperatures in the summer, but it's way below 0 degrees in winter, and it is one of the most northern deserts in the world. The Amu Darya river cuts across the desert, coming from the south-east and going in a north-west direction, Amu Darya practically splits the desert into almost two equal parts.