请选择DCBA-V6p;f9L+@2U4e8k6c7p0a:zHe is a letter his friend.7F;@5i8E0b
A. write，to7F;@5i8E0b
B. writing, to7F;@5i8E0b
C. write, for7F;@5i8E0b
D. writing, for7F;@5i8E0b