Simple spanish verb agreement help?

Question

Un dentista de la República Dominicana es ______. (dominicano/a)

I'm not sure if "dominicano/a" is supposed to be feminine or masculine because there's a "un" which means masculine [?] and it says "doctora" which seems feminine?

Answer 1

If you look at the indefinite article before dentista, you will see that it's masculine. The adjective should end in o.

All of the nouns having to do with occupations that end in ista can be masculine or feminine depending on the person to which it is referring to.

Answer 2

masculine because of un

Answer 3

Dominicano is correct because "un" signifies that the person/object is masculine. Some words seem feminine, but the "un" or "una" before the person/object shows if it's masculine or feminine.

Another example is lifeguard in spanish

Masculine: un salvavidas

Feminine: una salvavidas