Question

complete the sentence with the best relative pronoun. abby considers madelyn, shes known since kindergarten, the perfect companion.

Explanation:

The sentence has a non - restrictive relative clause modifying "Madelyn". The relative pronoun should refer to a person and be used in the object position of the clause. "Whom" is the objective form of "who" and is used to refer to people in relative clauses when they are the object of the verb in the clause. Here, "she's known (Madelyn) since kindergarten", so "whom" is appropriate. "Who" is subjective, "which" refers to things, and "that" is not used in non - restrictive relative clauses referring to people in this context.

Answer:

whom