♡ Answer ♡
D. Tu
♡ Step-by-step explanation ♡
<em> A/N (Author's Note): For context purposes, legitimate Spanish words, and (directly stated) translations will be in italics, which will make them look the same as this note. Happy reading (and have a fantastic day)!</em>
The keyword in this problem is <em>eres</em>. In Spanish, <em>eres </em>is another version of the word <em>ser</em>, which means <em>to be</em>. The form of <em>ser </em>depends on the context in which it is being used, as well as the corresponding subject (as in noun) intended. <em>Ser </em>is an irregular verb, which means its forms are quite different compared to most Spanish verbs.
The forms for the verb <em>ser </em>are as listed below:
‣ <em>soy </em>when using <em>yo</em>
‣ <em>eres </em>when using <em>tú</em>
‣ <em>es </em>when using <em>usted (Ud.)</em>, <em>él</em>, and/or <em>ella</em>
‣ <em>somos </em>when using <em>nosotros </em>and/or <em>nosotras</em>
‣ <em>sois </em>when using <em>vosotros </em>and/or <em>vosotras</em>
‣ <em>son </em>when using <em>ustedes (Usd.)</em>, <em>ellos</em>, and/or <em>ellas</em>
With this in mind, we can now find the form of <em>ser </em>being used, as well as the context it is mentioned in. As stated earlier, the keyword for this question is <em>eres</em>, which is a form of <em>ser</em>. Thanks to the list, we can clearly see that <em>eres </em>is used when the word <em>tú</em>, or words relating to <em>tú</em>, is/are present. In this case, only one answer choice makes sense in the sentence: <em>Tú</em>.
In order to expand your thought process, you can check the meaning of the sentence with the word <em>Tú </em>incorporated in it. <em>Tú </em>is the Spanish word for <em>you</em>. If <em>Tú </em>is being used, the word <em>eres </em>must agree with the word <em>Tú </em>(which it does). Out of the four answer choices, <em>Tú </em>is the only word that uses the same context as <em>eres</em>. They both agree with each other, and both use the 'you' context, which cause the sentence to translate to <em>You are Roberto</em>. This answer does indeed make sense, and each of the words are in mutual harmony/peace. Therefore, D. Tu is correct.
In other words, the answer to this question is D. Tu (because <em>eres </em>is intended to be used/paired with the word <em>Tú</em>).
