Which correctly identifies the bolded phrase in this sentence?

Whoever let the dogs out needs to go scour the neighborhood and collect them all.
Responses
A noun clausenoun clause
B adverb clauseadverb clause
C adjective clauseadjective clause
D prepositional phrase

A noun clause

In the sentence "Whoever let the dogs out needs to go scour the neighborhood and collect them all," the bolded phrase "Whoever let the dogs out" functions as a noun clause because it serves as the subject of the sentence.