What Drives the Continuation of the Antiquities Trade

What drives the continuation of the antiquities trade?

A) Wealthy collectors willing to pay high prices who create a market.
B) The native populations of poor countries who loot archaeological sites to feed their families.
C) Museums that are willing to accept artifacts without proper documentation of how they were acquired.
D) Unscrupulous archaeologists who secretly pocket any rare or otherwise valuable items during an excavation.