OG 11th 第78题。A 如何加强了

OG11th 第78题

In comparison to the standard typerwriter keyboard,the EFCO keyboard,which places the most-used keys nearest the typist's strongest fingers,allows faster typing and results in less fatigue.Therefore,replacement of standard keyboard with the EFCO keyboard will result in an immediate reduction of typing costs.

A.People who use both standard and EFCO keyboards report greater  difficulty in the transition from the EFCO keyboard to the standard keyborad than in the transition from the standard keyboard to the EFCO keyborad.

我选D。但是看答案时，不理解A、OＧ11th解释Ａ是加强。我不理解A的逻辑链如何加强结论的？

谢谢指点！