Answer :

una amiga vuestra, es (uno) de los vuestros

so B.. 

Answer:

The possessive adjective that can be modified to match gender and number is:

  • Vuestro.

Explanation:

The possessive adjective is a form of determinant that makes it possible to refer to the object or animal that someone possesses (directly), or to the familiarity that he has with a person (indirectly), in the case of the possessive adjective "vuestro," it has the particularity of changing allowing to identify the number and gender of the noun that is later, below I present the possible forms that it takes and the number and gender that refers:

  • Vuestro: Singular and male.
  • Vuestros: Plural and male.
  • Vuestra: Singular and female.
  • Vuestras: Plural and female.