Choose the correct word/ phrase to complete the sentence. She recently inherited a lot of wealth. Shes a/an _______.

The correct word is Heiress.
Possessor is defined as "a person who owns something or possesses a specific attribute." 'She possesses a great deal of riches,' we can say. However, simply saying, "She's a possessor," does not convey any information about what she possesses.
Heiress - A heiress is a woman who is legally entitled to or has inherited riches or property following the death of another person. Given its definition, it best depicts a lady who has lately inherited a large amount of money.
Trustee - A 'trustee' is someone who controls money or property in trust for someone else. It cannot relate to someone who has inherited a lot of money.
Empress - A woman who is a sovereign ruler of considerable authority and status, especially one who rules an empire, is referred to as an empress. Having a lot of money does not make you an empress. These two words have different meanings.