Answer:
The correct answer is A. "She came by just to say hello. She was so kind."
Step-by-step explanation:
The word "by" is a preposition that can be used to indicate movement or location. In this case, it is used to indicate that the woman came to the speaker's location. The word "on" is a preposition that can be used to indicate a surface or a location. In this case, it would not make sense to say that the woman came "on" to say hello. The word "in" is a preposition that can be used to indicate a location or a container. In this case, it would not make sense to say that the woman came "in" to say hello. The word "for" is a preposition that can be used to indicate a purpose or a reason. In this case, it would not make sense to say that the woman came "for" to say hello.