The landform that will most likely form where the new branch of the river empties into the ocean is a delta.
Deltas are formed when a river deposits sediment as it slows down and enters a standing body of water, such as an ocean or lake. The sediment builds up over time, creating landforms at the river's mouth. In contrast, a hill or mountain (referred to here as a "heel amount") would not be formed in this scenario, and a canyon typically forms in a different context, often due to erosion over time.