Which word in the sentence is the indirect object?

The instructor assigned each child a partner.

A.

instructor

B.

partner

C.

child

D.

each

For me the answer is letter c. child because in my own understanding indirect object is a noun phrase that refers someone or something which is affected by the action of the verb. So in the sentence "The instructor assigned each child a partner" the verb is assigned and the indirect object is child.