Which of the following contains a vague pronoun reference?

 - The nurse examined the patient as soon as she arrived.
 - The nurse examined the patient as soon as the patient arrived.
The second answer choice contains a vague pronoun reference. The pronoun she could refer to the nurse or the patient.
The first answer choice shows a possible correction for the vague pronoun reference. She has been replaced with the patient.
The nurse examined the patient as soon as the patient arrived.