I'm not really sure what you need in this sentence. Is it a verb? Do you
need to find the appropriate tense? If so, here is how I would do it:
Since the rise of his designs, Frank Lloyd Wright has been/has become an icon of modern architecture.
You
should use the present perfect tense because this is an action that
began in the past, but is still applicable in the present.
The answer to your question would be D is incorrect hope this helps
Answer:
were
Explanation:
It already happened, therefore you use were.
This is a simple sentence because in its entirety it is a single clause. There are no multiple independent clauses connected or any subordinate clauses to make it compound or complex.