For this chain-of-thought reasoning and answer, what was the question?
The relevant information to answer the above question is: The Tuotuo River ( , p Tuotuo He, lit. "Tearful River" is the official headstream of the Yangtze, and flows 358 km ( 222 mi) from the glaciers of the Gelaindong Massif in the Tanggula Mountains of southwestern Qinghai to the confluence with the Dangqu River to form the Tongtian River. )
A: The Tuotuo River
Q: The Tuotuo River ( , p Tuotuo He, lit. "Tearful River" is the official headstream of the Yangtze, and flows 358 km ( 222 mi) from the glaciers of the Gelaindong Massif in the Tanggula Mountains of southwestern Qinghai to the confluence with the Dangqu River to form the Tongtian River. ) In Mongolian, this section of the river known as the Ulaan Moron or the "Red River".

Based on this passage, what is the source of the yangtze river?