根据短文内容，选择正确答案。
A
    Mr. Black is walking in the park. He is tired. He wants to have a rest. He sees a green chair under a big tree. So he walks to the chair. There is another man in front of him. He is walking to the chair, too. He has a board (木板) in his hand. Mr. Black is very worried. He begins to run quickly. The man sees him and begins to run, too. But Mr. Black gets to the chair before the man. He is very happy and sits in the chair. When the man comes, he says nothing but gives Mr. Black the board. The board says, “Wet Paint.”