The correct options are
B These rivers usually begin their journey from the slopes of the Himalayan mountains
C Some rivers originate from the Aravalli mountains too.
D Some rivers in the Terai region emerge from the slopes of southern Himalayas and disappear in the foothills of the Bhabar region.
The type of river system that drains within the land area, is known as the internal drainage system. In India, these rivers usually begin their journey from the slopes of the Himalayan mountains, especially from Shivalik hills and Ladakh region. There are some rivers in the Terai region, which after emerging from the slopes of southern Himalayas, disappear in the foothills of the Bhabar region.