已知1nm等于一根头发丝的直径的六万分之一，则一根头发丝的直径为（    ）m（1nm=10^﹣9m）

As we know, a schedule may be more appropriately expnessed and analyzed if it is put         a graph.

A．in the direction of

B．in the process of

C．in the form of

D．in the shape of