I think the answer is metal
It's a very long sentence with a lot of information, but it is still only a simple sentence (option b): it has only one verb (taught). In order to qualify as a complex or compound-complex sentence, it would have to have at least 2 phrases, each with a different verb.
The process in 1990 in which the German democratic republic joined the federal republic of Germany. They removed Hungary's boarder fence with Austria it caused an exodus of thousands of east Germans fleeing to west Germany and Austria via Hungary.
He wanted to create ethical models for people and he made Confucianism.
I hope this helps
The answer is A. Frank Lloyd Wright