so, if my professor is asking for me to choose an ethnic goup to which I personally belong can I choose Hispanic/American?

Yes, definitely.

To determine which ethnic group you personally belong to, you should consider your own cultural background, heritage, and personal identity. If you identify as being of Hispanic or Latin American descent and you also hold American citizenship, then you can choose Hispanic/American as the ethnic group to which you personally belong. It's important to choose the ethnic group that best represents your own cultural and ethnic background.