Which personal pronoun best completes the sentence? how is it used? at first they wouldn't admit to the deed, but later they said, "the ones who did it are "
a. we; predicate nominative
b. us; subject
c. we; subject
d. us; predicate nominative

In the sentence: At first they wouldn't admit to the deed, but later they said, "The ones who did it are ."  

The personal pronoun best completes the sentence is letter b: ‘us’ and it is used as ‘subject’.  

Pronouns are utilized as substitutes for a noun. In order for it to substitute, it must have a clear antecedent. Personal pronouns are used to substitute nouns with ownership. There are three persons point of view.1st person is when the subject is the one who is speaking (e.g. I, me, my, mine, we, us, our, ours). 2nd person is when the subject is the one being spoken to (you, your, yours). 3rd person is when the subject is the one spoken about (he, him, his, she, her, hers, it, its, they, their, theirs).