The author says that the "lead" in a pencil__A．is

单项选择题

Questions 41 to 44 are based on the following passage: The lead pencil is one of the most used pieces of merchandise in the world. It is the simplest, most convenient and least expensive of all writing instruments. Perhaps the most surprising thing about the lead pencil is that it is not lead at all. And it is not a pencil. The "lead" is actually graphite from the Greek word "to write." The word "pencil" is from Latin. The first pencils were fine or stiff brushes of hair. American pencil makers turn out their product by the millions. Probably there is no more useful article in the world. As one wise person remarked: "Everything begins with a pencil. Whether it’s a pin or a battleship, it is first rendered with a pencil." There is a pencil for every purpose. In fact, the industry now supplies 370 different types and styles in more than 70 different colors and in 18 degrees of hardness. Some write clearly on slippery surfaces, such as glass and plastic. Surgeons use a special pencil for outlining the operation area on the patient’s skin, and packing-plants use another type to write identification on sides of beef. There is even a special electric pencil used for tests checked by electronic machines. There are many novelty pencils. Some have the Ten Commandments, calendars or the multiplication table on them. Some are in the shape of umbrellas, canes, baseball bats and traffic signals. One may be 12 feet long, while others are only 1/2 inch. One recent novelty is a pencil with paper in it. A small roll of paper fits in the center of the pencil and is drawn out through a slit in the side. It’s just the thing for those who are always looking for a scrap of paper A popular idea is that a check, will, or other legal paper whiten in pencil is not legal. This is not true. Any legal document which does not specify otherwise can be legally signed in pencil.

The author says that the "lead" in a pencil__

A．is graphite
B．is really a chemical
C．comes from Greece
D．is hard to find