choose the correct indefinite article for the following word.\nmaestro\n\nun\nuna\nunos\nunas

Brief Explanations:

In Spanish, "maestro" is a masculine singular noun. The indefinite article for masculine singular nouns is "un". "Una" is for feminine singular, "unos" for masculine plural, and "unas" for feminine plural. So the correct indefinite article for "maestro" is "un".

Answer:

A. un