Respuesta :
The answer to the question above is A, that is, "the archaeologist, with her assistants, has studied carvings". The agent, the doer of action, the one that mainly carried out the study is the archaeologist. This NP is singular and therefore the verb should also be singular (3rd person singular). That is why this is the sentence in which the verb agrees with the subject: both the verb and the subject are in the 3rd person singular, agreeing in number and person.