Answer:
Object of a preposition
Explanation:
The noun clause of the sentence is “whomever passed them” because it is a group of words having a subject (whomever) and a verb (passed), acting as a noun and which can be referred to with pronouns like “it” and “that.” As a noun, this clause functions as the object of the preposition “to” because it is placed next to this preposition and completes its meaning (the proposition would not make sense without this clause).
