某同学想研究悬挂小球的悬线拉力与斜面AB夹角α的关系。他用悬线拉着小球静止在光滑斜面上。通过移动斜面，改变悬线与斜面AB夹角α的大小，用弹簧测力计测出悬线拉力的大小。实验过程及实验现象如图所示。

小明在显微镜的视野中看到一个“d”字，请问透明纸上写的是（  ）

阅读理解
Once there lived a very clever man whose name was Aesop (伊索). One day as he was taking a walk, he came across a traveler. The traveler stopped him and asked, “Excuse me,, can you tell me how soon I’ll get to town?”
“Go.” Aesop answered.
“I know I must go.” said the traveler, “but I want to know how soon I’ll get to town.”
“Go! ”Aesop said again angrily.
“This man must be mad(疯的),” the traveler thought and went on.
After the traveler had gone some distance(一段距离), Aesop shouted after him, “You’ll get to town in two hours.”
The traveler was greatly surprised. He turned back and asked, “Why didn’t you tell me that before?”
“How could I tell you that before?” Aesop answered, “I didn’t know how fast you could walk.”