Answer:
Minnesota, the top yellow one
Explanation:
The map literally tells you.
Anvil is a tool used by blacksmiths, and it is the surface on which the object is placed which is worked on with a hammer- stroked with a hammer.
von Bülow meant (in 1899) that Germany will either have to colonize others ( be the hammer) or it would have to risk being colonized itself (being the anvil), hence showing the need for Germany to participate in colonization.
