When he ______ home. His mother was cooking

A. arrived in        B. got                 C. got to             D. reaching

When he ________ home, his mother had left．

1. A.
   is back
2. B.
   was back
3. C.
   is back to
4. D.
   was back to

— My brother hurt his legs when he rode his bike on the way back home.
— ______.