Which of the following contains a vague pronoun reference?

 - Mrs. Griffith was overjoyed when she saw her granddaughter for the first time in two years.
 - When Mrs. Griffith saw her granddaughter for the first time in two years, she was overjoyed.
The first answer choice contains a vague pronoun reference. The pronoun she could refer to Mrs. Griffith or her granddaughter.
When Mrs. Griffith saw her granddaughter for the first time in two years, she was overjoyed.
The second answer choice shows a possible correction for the vague pronoun reference. The text has been rewritten so that the meaning is clear.
Mrs. Griffith was overjoyed when she saw her granddaughter for the first time in two years.