What is the function of the relative pronoun in the clause?

howard carter, whose tenacity was unmatched in searching for king tut's tomb, led to the discovery of this buried treasure.

a. possessive
b. subject
c. direct object
d. object of a preposition

Among the choices provided above, the correct function of the relative pronoun in the clause is:

A. possessive

There are various kinds of relative pronouns including who, whom, which, whose, which, and that. The relative pronoun used in the sentence refers to Howard Carter's incomparable tenacity in searching King Tut's tomb.

hm, switch the relative; nominative and indefinite; objective ? not too bright in the knowledge of the english.