Which of the following contains a vague pronoun reference?

 - Peter's brother John wondered whether he ran fast enough to qualify for the Boston Marathon.
 - Peter's brother John wondered whether Peter ran fast enough to qualify for the Boston Marathon.
The first answer choice contains a vague pronoun reference. The pronoun he could refer to Peter or John.
The second answer choice shows a possible correction for the vague pronoun reference. He has been replaced with Peter.
Peter's brother John wondered whether Peter ran fast enough to qualify for the Boston Marathon.