请根据下面的短文回答以下各题。 Mr and Mrs Green lived in a big city, and one summer, they went to the country for their holiday. They enjoyed it very much, because it was a quiet and clean place. One day they went for a walk early in the morning and met an old man. He lived on a farm, and he was sitting in the warm sun in front of his house. Mr. and Mrs. Green asked him, "Do you like to live in this quiet place" The old man said, "Yes, I do." Mr. Green said, "What are the good things about it" The old man answered, "Well, the people know each other. They often come and visit me, and I often go and visit them. And there are also many children here." Mr. Green said, "That’s interesting. And what are the bad things" The old man thought for a moment, and then said, "Well, the same things really.\ Mr. and Mrs. Green took a walk ______.

A. early in the morning
B. in the afternoon
C. after supper