The correct answer is: [C]: "décimo" .
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Don't forget the accent mark.
Note: The noun—"el piso"— is singular and masculine; hence, the correct answer is:
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Answer choice: [C]: "décimo" .
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Choice [A]: "décima" ; would refer to a noun that is singular and feminine.
So; rule out this option.
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Choice [B]: "décimos" ; would refer to a noun that is plural and masculine; OR: a noun that is plural, AND (a mixture of at least one masculine AND one or more feminine).
So; rule out this option.
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Choice [D]: "décimas" ; would refer to a noun that is plural and feminine.
So; rule out this option.
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Answer choice: [C]: "décimo" ; would refer to a noun that is singular and masculine; which is the correct answer choice.
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