Teresa has a contract to teach eighth grade at Washington Middle School. She decided she could make more money writing a book, so she assigns her teaching contract to her friend, Shirley, who is also a licensed teacher. The duties under the teaching contract

The duties under the teaching contract cannot be delegated

Explanation:

The person wit whom the school has a binding agreement was Teresa and contract of services cannot be delegated unilaterally by Teresa to her friend Shirley without consulting the school authority.

The appropriate procedure would be for Teresa to discuss with the school her plans to let Teresa to cover up for her absence, however, if the school accepts the new arrangement, Teresa would need to be relieved of her duties as this would be a permanent substitution.