Final answer:
Retrogradation is the movement of a shoreline landward due to lower sedimentation rates compared to subsidence, while regressive and transgressive are related to exposures and submergences of land due to sea-level changes, respectively. The correct answer is option: an erosional process causing a shoreline to retreat inland.
Step-by-step explanation:
The process of retrogradation refers to the landward retreat of a shoreline that happens when the rate of sedimentation is slower than the rate of subsidence. This geological change can wildly reshape the coastline impact on ecosystems and human settlements.
Regressive and transgressive are terms associated with the relative sea-level changes, where regressive refers to the exposure of formerly submerged seafloor due to a fall in sea level, and transgressive involves the submergence of land under the sea because of a rise in sea level.
Movements of the earth's crust, changing climates, and alterations in sediment supply all contribute to these processes. Understanding these concepts is important for recognizing how coastlines have evolved over time and predicting how they may continue to change in the future.