her

Usage note:
Traditionally, the masculine singular pronouns he¹, his, and him have been used generically to refer to indefinite pronouns like anyone, everyone, and someone (Everyone who agrees should raise his right hand) and to singular nouns that can be applied to either sex (painter, parent, person, teacher, writer, etc.): Every writer knows that his first book is not likely to be a bestseller. This generic use is often criticized as sexist, although many speakers and writers continue the practice.
Those who object to the generic use of he have developed various ways of avoiding it. One is to use he/she or she/he (or he or she or she or he) or the appropriate case forms of these pairs: Everyone who agrees should raise his or her (or her or his or his/her or her/his) right hand. Forms blending the feminine and masculine pronouns, as s/he, have not been widely adopted, probably because of confusion over how to say them.
Another solution is to change the antecedent pronoun or noun from singular to plural so that the plural pronouns they, their, and them can be used: All who agree should raise their right hands. All writers know that their first books are not likely to be bestsellers. See also they.