Final answer:
In 2017, based on the provided information, a delta likely formed because of deposition. The Mississippi River delta is an example where sediments precipitate as freshwater meets seawater, creating a delta at the mouth of the river.option C is correct answer.
Step-by-step explanation:
Based on the reference information provided, it seems that this question is pertaining to formations caused by various geological processes. One of the key processes mentioned is deposition, which is significant in the creation of new landforms such as deltas and islands. When looking at a satellite photograph depicting changes over time, such as the Mississippi River delta's transformation, the process responsible is typically either erosion or deposition.
In this scenario, the formation of a new landmass is more likely due to deposition, where sediments carried by the river water are laid down at the mouth of the river, especially where it meets seawater. This depositional process can result in the creation of a delta (if the landmass is attached to the mainland) or an island (if the landmass is independent of the mainland).
Considering that deltas are created by sediment carried by rivers and deposited at their mouth, and there is no specific information in the references referring to volcanic activity (associated with the formation of islands), the most likely answer to 'What likely happened in 2017?' is Option C: A delta formed because of deposition. The references given also mention the Mississippi River delta and processes like sea-level rise and transgression, which are related to the deposition and formation of deltaic landforms.