Final answer:
The legal category of the UAC's second cousin marrying the UAC's sponsor depends on the state laws.
Step-by-step explanation:
Regarding the question of what category is the UAC's second cousin legally married to the UAC's sponsor, it's important to note that laws regarding cousin marriage vary across states in the United States. In some states, first-cousin marriage is legal, while in others it is prohibited.
Therefore, the legal category of the UAC's second cousin would depend on the specific state laws where they reside. If the state allows first-cousin marriage, then the UAC's second cousin can legally marry the UAC's sponsor. However, if the state prohibits first-cousin marriage, then the marriage would not be legally recognized.