阅读下面短文, 从短文后各题所给的四个选项(A、B、C、D)中, 选出可以填入空白处的最佳选项。

    One summer,when I was little,my dad built me a lemonade stand（柠檬水摊位）.On sunny days I'd1the stand outside the local car wash with a cooler and my little black safe（保险箱）.I didn't get many customers2I always had fun.

    One3I did have was an elderly gentlemen who4across the street from the car wash.He would come every day and5a glass of lemonade for his wife.Even though I only625 cents,he always paid7with a $1 Sacagawea coin.So I built up quite a collection by the end of that8!

    Now,as a college student,I make it a9to stop at as10lemonade stands as I can,always paying11than the kids charge me.This has been going on for12three years now.But this week,I didn't have any13with me when I stopped at a little girl's stand.I14around in my car frantically（疯狂地）and finally opened up one of my boxes.I opened it up and sure enough,there were my Sacagawea coins.I almost shut the lid（盖子）again because they15so much to me,but then I realized that that was16why I had to pay with the coin.When I gave that17girl the shiny gold coin,I said "You should keep this one,they don't make them anymore!".And her18lit up.As I drove away,I saw her running to her sister to show her the19and I knew that I had made her just as20as I was when I was a little girl.