Which one of the following is the cause of long-term sea-level change?

Long-term sea-level changes, often referred to as eustatic changes, are primarily driven by alterations in the total volume of ocean water or the capacity of ocean basins. The melting of land-based ice sheets, such as those in Greenland and Antarctica, is a major driver of global sea-level rise over centuries and millennia [4]. While thermal expansion (change in marine water density) also contributes to sea-level rise, the melting of massive ice sheets represents a catastrophic long-term factor that can raise levels by tens of meters [4]. In contrast, atmospheric disturbances like storm surges are short-term, localized events caused by pressure gradients and winds [5]. Furthermore, the melting of icebergs (floating ice) does not significantly change sea levels because they already displace their own weight in water, unlike land-based ice sheets which add new mass to the ocean.

Sources

1. [1] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 7: Climate Change > 5. sea level rise > p. 14
2. [4] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 12: Major Crops and Cropping Patterns in India > Antarctic Ice Sheet > p. 74
3. [2] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 20: Impact of Climate Change > 2O.3. RISE IN SEA LEYELS > p. 276
4. [3] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 8: Natural Hazards and Disaster Management > surge, sea-surge or storm surge > p. 57
5. [5] https://sealevel.nasa.gov/understanding-sea-level/regional-sea-level/short-term-effects/