Read the text and choose the correct part to complete the sentence.
In the beginning, I put it down to a simple case of exam nerves. My daughter Sarah had just turned sixteen and was studying hard for her GCSEs. I knew she’d do well, as she was top of the class in all her subjects at school and had always been a high achiever. But as the time for the exams drew nearer, her behaviour started to change – drastically.
At first, the writer believed her daughter’s behaviour had changed because Sarah ...

• was worried about academic success.
• had always been very intelligent.
• was having problems at school.
• had just turned sixteen.