Final answer:
Susan's decision to try out for volleyball came as a shock to her family because she had never shown interest in sports before.
Step-by-step explanation:
The correct answer is a) She had never shown interest in sports before.
Susan's decision to try out for volleyball came as a shock to her family because she had never shown interest in sports before. This means that Susan's family was surprised because she had never expressed an interest in participating in any sports activities in the past.
For example, if Susan had always preferred reading or playing musical instruments over engaging in physical activities, her decision to try out for volleyball would be unexpected for her family.