How is the underlined pronoun used in the sentence?

Believe it or not, Mr. Archer told us the whole history of the washing machine. us is underlined

A. indirect object

B. direct object

C. object of a preposition

The underline pronoun which is "us" is used as an indirect object since it tells to whom of for whom something is to be done. The indirect object pronouns are the replacement fro indirect object or noun which is always personal nouns.

Find the verb first.

-told

ask who or what to find the subject.

told who or what?

Mr. Archer

ask who or what to find direct object.

Mr. Archer told who or what?

history

ask to who or to what to find indirect object.

Mr. Archer told history to who or to what?

us.

so, "us" is an indirect object.