The answer is D. Tenth amendment. The governor, in matters of homosexual marriage and the legalization of marijuana, disagreed with accepting them in Texas, and since the tenth amendment gives freedom to states to have their own decisions, he has always defended Texas autonomy by using such amendment, to reject those changes in the Constitution. But many have argued that while the Tenth Amendment defends the rights of states, it can't be applied in all cases, because the changes that Rick Perry wants to avoid are issues to be considered or discussed in a modern and inclusive society.