Which explains upwelling in the oceans?

Acoastal winds blow cold surface water out to sea. deeper, nutrient-rich, warm water flows upward to replace the surface water.
Bwind near the coastline blows warm surface water away from the land. deeper, nutrient-rich, cold water flows upward to replace the surface water.
Csolar heating near the coastline heats cold surface water, which diffuses out to sea. deeper, nutrient-rich, warm water flows upward to replace the surface water.
Dsolar heating near the coastline heats warm surface water, which diffuses out to sea. deeper, nutrient-rich, cold water flows upward to replace the surface water.