What Is the Implicit Premise in the Following Moral Argument

Multiple Choice

What is the implicit premise in the following moral argument? "Same-sex marriage is contrary to tradition. Therefore, it should never be allowed."

A) Same-sex marriage is harmful to society.
B) Same-sex marriage is unnatural and therefore should be banned.
C) Whatever causes harm to children should not be allowed.
D) Whatever is contrary to tradition should not be allowed.