The correct use of the verb "ser" is not listed in your options. However, if we consider the correct conjugation of "ser" in the second person singular, it should be "tú eres" instead of "tú ere."
Here’s a breakdown of your options:
- "yo estoy" is the correct form of the verb "estar."
- "ella está" is also the correct form of "estar."
- "tú ere" is incorrect; it should be "tú eres."
Therefore, none of the options provided correctly use the verb "ser." The correct form is "tú eres."