A political viewpoint that favors native inhabitants over immigrants is the best description of a Nativist.
Option 1
A nativist by definition is a person or a public viewpoint that favors the provision of better privileges and rights to native residents and inhabitants of an area as opposed to immigrants who merely shifter to the area. A nativist is not a politician related to and favoring only Roman Catholics to office as it relates to all natives and not just Roman Catholics.
A Nativist isn’t necessarily cruel but every cruel leader isn’t a Nativist. A Native American activist is also a decent description but a native activist need not support natives exclusively, just because he is native, making option 1 the best answer.