In which sentence is the relative pronoun used within the object of a preposition?

The second sentence is the only one which has a relative pronoun within the object of a preposition: This is the flag designer of whom I have spoken.

Explanation: the relative pronoun in the sentence is "whom" and it is placed between the preposition (of) and the object of the preposition (I have spoken).

All of the other sentences have no relative pronouns placed between prepositions and their objects.

i prefer dogs : ) they are floofyyy

citizens are given 25 years of life to prove their worth to society; if they fail to do great things