Why Are the Mediterranean and Black Seas Prone to Heavier

Why are the Mediterranean and Black Seas prone to heavier loads of pollution than the Atlantic Ocean and North Sea?

A) The countries bordering the Black and Mediterranean Seas are home to industries that create higher levels of pollution.
B) Higher temperatures in the Atlantic Ocean and North Sea cause pollution to biodegrade much more quickly.
C) The Atlantic Ocean and North Sea are part of or closely connected to the circulating flow of the world ocean, allowing them to disperse pollution more easily.
D) The Mediterranean and Black Seas support heavier populations, which create more human and industrial waste.