Answer:
The correct answer is Primo.
Explanation:
Of all the options given, the only word that matches in gender for the indefinite determinant "un" is the word primo.
The other words are words of the female gender, therefore they would only be accepted if the word "una" was there.
The masculine nouns are those words ending in -L, -O, -N, -E, -R, -S.
The feminine nouns in Spanish are the words ending in -A, -D, -ÓN, -Z.
With the exception of words ending in -MA, -TA, as they are masculine words.
