[单选题]

Wolfgang's father told him he couldn't play the piano yet because______.
A． his sister was taking lessons
B． he had to help his mother
C． he was too small
D． he had to wait for his sister to finish practising

Wolfgang's father told him he couldn't play the piano yet because______.A． his sister was taking lessonsB． he had to help his motherC． he was too smallD． he had to wait for his sister to finish practising