What did the emperor ask Ma Lian to paint?
1. The emperor asked Ma Liang to paint a gold tree and a boat.
2. The emperor asked him to paint a gold tree and a boat.
3. He asked Ma Liang to paint a gold tree and a boat.
4. He asked him to paint a gold tree and a boat.
(Which one is the right answer for the question?)
All of those can be correct grammatically.
The first one gives the clearest information.