Which of the following contains a vague pronoun reference?

 - Even after Tim warned Julia to be careful, she broke his handmade ceramic bowl when she dropped it on her foot.
 - Even after Tim warned Julia to be careful, she dropped his handmade ceramic bowl on her foot and broke it.
The first answer choice contains a vague pronoun reference. The pronoun it could refer to his handmade ceramic bowl or her foot.
Even after Tim warned Julia to be careful, she dropped his handmade ceramic bowl on her foot and broke it.
The second answer choice shows a possible correction for the vague pronoun reference. The text has been rewritten so that the meaning is clear.
Even after Tim warned Julia to be careful, she broke his handmade ceramic bowl when she dropped it on her foot.