Final answer:
The South China Sea currents do not explain the connection between high-elevation mountains and large rivers in the South Asian realm, unlike monsoon rains, seasonal snowmelt, and high-relief drainage that contribute to the rivers' flow.
Step-by-step explanation:
Among the given options, the one that does not explain the connection between high-elevation mountains and large rivers in the South Asian realm is South China Sea currents. Monsoon rains, seasonal snowmelt, and high-relief drainage are all contributing factors to the presence of large rivers in South Asia, originating from or influenced by the Himalayas. These factors contribute to the rivers' water volume through seasonal patterns such as the monsoon rains, which bring moisture from the Indian Ocean, and the melting of snow from the high mountain ranges.
The connection lies in the unique climatic and geographical conditions of South Asia, where the monsoon system plays a pivotal role in replenishing river basins, thereby supporting early civilizations and current population centers centered around these rivers. In contrast, the South China Sea currents influence the climate and marine systems quite remotely from the rivers that originate in the high mountains of South Asia.