---I saw Betty go to Grandpa Zhang’s home just now.

---Yes. She is often seen ______ the old man with his housework.

1. A.
   help
2. B.
   to help
3. C.
   helps
4. D.
   helped

—I saw Betty go to Grandpa Zhang’s home just now.

—Yes. She is often seen ________ the old man with his housework.

[　　]

?I saw Betty go to Grandpa Zhang's home just now.　　

?Yes, she is often seen ________ the old man with his housework.

A. help

B. to help

C. helps

D. helped