The correct answer is - D. The Huang He flooded without warning or predictability.
The difference between the Huang He River, most commonly known as the Yellow River, and the Nile River, is that the Nile had very predictable seasonal flooding, while Huang He was the total opposite, it was very unpredictable and was flooding the surrounding area multiple times during a year. This was because of the influences that this two rivers have, in the sense of water reception.
The Nile, in general, runs through desert, and it only gets bigger amount of water when the seasonal rainfall occurs on the East African highlands. The Huang He, on the other side, was influenced from multiple different rainfalls that could have appeared at any time of the year, and on top of that, the big amounts of snow were also coming into it when they were melting, thus flooding multiple times, and without warning.