The correct answer is A. Papel
Explanation:
In Spanish language, it is common all nouns or words that refer to animals, objects, people, places, etc have a specific gender in terms of grammar, this implies feminine nouns are preceded by articles such as "la", "las", "una", "unas" that are equivalent in English to a/an, the while masculine nouns are preceded by the articles "el", "los", "uno", "una that also represent a or the in English.
Besides this, there are general rules to identify masculine nouns, this includes that most masculine nouns end in -o, -e or consonants such as -l, -r or -n, this includes words such as libro (book), hombre (man), papel (paper), amor (love) or canal (channel). However, there are some exceptions, for example, mano (hand), piel (skin) y leche (milk) are feminine nouns preceded by "la" despite they have common masculine endings.
According to this, the one that is a masculine noun is "papel" because it ends in the consonant "-l" that is common in masculine nouns and also is preceded by the article "el" or "un" that indicates masculine. For example, "el papel esta sobre la mesa" (the paper is on the table).
