求解一道题~~~

羊绒

Manufacturers of mechanical pencils make most of their profit on pencil leads rather than on the pencils themselves. The Write Company, which cannot sell its leads as cheaply as other manufacturers can, plans to alter the design of its mechanical pencil so that it will accept only a newly designed Write Company lead, which will be sold at the same price as the Write Company's current lead.

Which of the following, if true, most strongly supports the Write Company's projection that its plan will lead to an increase in its sales of pencil lead?

• AFirst-time buyers of the mechanical pencils tend to buy the least expensive mechanical pencils available.
• BAnnual sales of mechanical pencils are expected to triple over the next five years.
• CA Write Company executive is studying ways to reduce the cost of manufacturing pencil leads.
• DA rival manufacture recently announced similar plans to introduce a mechanical pencil that would accept only the leads produced by that manufacturer.
• EIn extensive text marketing, mechanical-pencil users found the new Write Company pencil markedlysuperior to other mechanical pencils they had used.
  

想知道B为啥不对，因为我认为既然预期的铅笔销量会上升，那么配套的笔芯不也就上升了吗

Maxcorn

B说的只是mechanical pencils 销量上升， 没有说Write Company的mechanical pencils的销量也上升。 overgeneration