instruction: Is the next sentence syntactically and semantically acceptable?

John's mother sent a letter to Mary.

response: acceptable

instruction: Is the next sentence syntactically and semantically acceptable?

The man who I gave John this picture of was bald.

response: unacceptable

instruction: Is the next sentence syntactically and semantically acceptable?

The dog flopped in the comer.

response: acceptable

instruction: Is the next sentence syntactically and semantically acceptable?

They talked to Kim and to each other.

response:
acceptable