The subordinate clause in the sentence is option D: whereas Gordon preferred to play baseball.
A subordinaye clause is one which do not form a complete sentence, it depends on the other part of the sentence to have a total sense.
A subordinate clause, also known as a dependent clause, will begin with a subordinate conjunction or a relative pronoun and will contain both a subject and a verb.
In this case the word whereas indicates that it is a subordinate clause since it is a subordinate conjunctions.
The real answer is the impact of land policies pursed by georgia so that hey could see what type of land we had because of the white people taking all black people to build in now what is called georiga